During this episode, Detective Johnson and Dr. Williamson describe how decades of determined police work and cutting-edge forensic science identified Joe Michael Ervin as the person who assaulted and murdered four women between 1978 and 1981.
Also read the corresponding blog post.
This transcript has been edited for clarity and brevity.
KAREN FRIEDMAN: Welcome to Justice Today, the official podcast of the Department of Justice's Office of Justice Programs, otherwise known as OJP, where we shine a light on cutting edge research and practices and offer an in-depth look at what we're doing to meet the biggest public safety challenges of our time. Join us as we explore how funding science and technology help us achieve strong communities.
I'm your host, Karen Friedman, the Director of Criminal Justice Innovation, Development, and Engagement at OJP's Bureau of Justice Assistance, otherwise known as BJA.
Earlier this year, police in Denver, Colorado, announced that they had solved the cold-case murders of four women who were killed about 40 years ago, all of whom were the victims of one man—a previously unknown serial killer named Joe Michael Ervin.
The story was chillingly real but sounded like a crime novel. In the late 1970s and early 80s, Ervin took the lives of four women who appeared to have nothing in common. They differed in age, race, and appearance. At the time, the cases did not appear to be related, and Ervin was never a suspect in any of them. Shortly after the fourth murder, Ervin shot and killed a police officer during a traffic stop and took his own life in jail.
How, after so many years, was the truth uncovered? It took years of old-school police work and a cutting-edge investigative technique called forensic genetic genealogy. It took the combined efforts of police in Colorado and Texas and support from our agency, BJA. And it took the efforts of our two guests today, who were instrumental in solving this mystery.
Detective Kari Johnson of the Denver Police Department led the investigation that tied these four murders together and linked them to Ervin. And Dr. Angela Williamson, the Forensic Unit Supervisor here at BJA, worked with Detective Johnson to coordinate the forensic work and two separate BJA grants that were crucial to finding the killer.
Welcome Kari and Angela. Thank you so much for joining me today. It's so great to have both of you with us today.
KARI JOHNSON: Hi, Karen. Thank you so much for having us.
KAREN FRIEDMAN: Angela, how are you today?
ANGELA WILLIAMSON: I am doing great and really honored to be here to talk about this amazing work and the answers that were able to be provided because of our joining forces.
KAREN FRIEDMAN: This is a remarkable story and the work that both of you did is really fascinating. Kari, let's start with you. I understand that you inherited some of these cases when you joined Denver's cold-case squad. When did you start working on them and what did you know about these murders initially?
KARI JOHNSON: So, I did inherit these cases, although I didn't inherit them until 2018. I joined the cold-case unit in Denver in 2016, and at the time, three of these four cases were assigned to a friend and co-worker of mine named Jamie Cisneros. She's now a detective in the homicide unit. She was actually assigned as the lead investigator on these cases before I was.
I first learned about them when Jamie and I flew down to North Carolina in 2017 to interview and collect DNA from a gentleman there. There had been a report in the case of Madeleine Livaudais, who was our first victim in 1978, that somebody had observed what they thought was a TV repair van parked in front of Madeleine's home on the day that she was found murdered. Jamie had done a phenomenal job of tracking down an individual who had at the time worked for a TV repair company in the area of Madeleine's home. So that was my first introduction to the cases.
Jamie subsequently moved over to the homicide unit. And in 2018, we received our CODIS match to our fourth victim, Antoinette Parks. She's actually the victim from Adams County (outside Denver). Our three victims’ unknown suspect DNA profile had been in CODIS for quite some time, and then in 2018, a fourth matched up.
KAREN FRIEDMAN: Kari, could you explain what CODIS is?
KARI JOHNSON: Sure. CODIS is the Combined DNA Index System. It's a nationwide database in which offender DNA is uploaded and then unknown DNA profiles can be added. It runs a systematic search on a consistent basis to determine if unidentified DNA profiles can be matched to identified profiles within that system.
KAREN FRIEDMAN: So, as new DNA comes into the system, if there's something even from years ago, it would match up new DNA with old DNA, correct?
KARI JOHNSON: Correct. As long as there's a known offender sample in the database, any DNA that's put in should match to that offender.
KAREN FRIEDMAN: Is DNA taken from the crime scene, or how does that work, exactly?
KARI JOHNSON: It can be collected from a variety of sources. In these cases, for example, we had DNA collected from the scene for one victim. We had DNA collected from the bodies of the victims themselves. We had DNA collected from undergarments of one of the victims. We can also collect DNA from other things, like a cup or a handgun or a knife. If there’s a sufficient profile that can be developed and put into CODIS, that can lead us down the road further in our investigation.
KAREN FRIEDMAN: So, you come to a crime scene, you collect all the DNA, you separate out the DNA of the victim, and all the DNA that's left gets uploaded to the system. Is that correct?
KARI JOHNSON: Correct. As long as it’s a sufficient profile. That's all very science-y. The science guys do a great job of separating that out. Sometimes you can have mixed profiles and they have to separate those mixed profiles out. They do a fantastic job of that.
KAREN FRIEDMAN: So, in 2018 you identified a fourth victim?
KARI JOHNSON: Yes. Before 2018, we had identified three victims who were killed over a period of two and a half years. And from those victims, the unknown offender – we didn't know who he was at the time – DNA profile was developed. When I inherited the cases in 2018, all I knew was that there was an unknown male offender who was responsible and connected to these four victims. And that unknown offender profile was in CODIS. Does that ultimately turn out to be Joe Michael Ervin? It does. But we don't know that at the time.
Over the years, other cold-case investigators had done a lot of legwork. They'd identified suspects and, either through consent or a warrant, they had obtained their DNA. Then that was sent to the lab, and those profiles were then compared against our offender DNA. Subsequently, I would say 99 percent of those initially named suspects were eliminated through the lab process.
KAREN FRIEDMAN: So, Angela, that's where you came in. At this point, investigators had a new tool in their toolbox called forensic genetic genealogy, or FGG. Angela, you are one of the country's leading authorities on FGG. Can you tell us how that works?
ANGELA WILLIAMSON: Sure. For quite some time now, genealogists have been using publicly available ancestry databases. You see the ads on TV where you can submit your own DNA sample, which is usually just saliva from your mouth on a swab. And based on the DNA, then you can trace your ancestry. You can find third cousins four times removed that you never knew existed.
Using that same methodology, you can upload a DNA profile from an unknown person – in this case, an unknown murderer. Then you can mine these databases to see if you can find any relatives. Now, I want to emphasize that there are only two databases in the U.S. right now that allow law enforcement to utilize their data to try and further investigations. All the contributors that have put DNA in these databases sign a consent form saying that they allow their DNA to be used for investigative purposes. So, law enforcement only has access to consenting contributors to these databases.
And, typically, when you are looking for family matches, it's not the person who's responsible for the crime. It's usually not even a close relative, like a sibling. It's often a very distant relative, like a third cousin twice removed. And then that's where the hard work comes in. We have a potential lead to a potential family. We try to figure out, how do we narrow that down to who this might be?
KAREN FRIEDMAN: That's really interesting. But it's certainly not a quick fix or an instant solution.
ANGELA WILLIAMSON: No. Because we read about these cases every day, I think there's a misperception that, wow, FGG is the answer to everything. Firstly, the DNA process is very complicated. I am a DNA expert. It is a process I was never trained in, and I'm not going to lie, I don't need to be. There are expert labs in the country and there's just a few of them that do this work. It is quite expensive. It costs anywhere from $3,000 to $5,000 per sample. And not every sample will be good enough for this technology.
It comes down to how much DNA you have, and the quality of that DNA, which is often problematic in cold cases. And DNA is a biological entity. With time, with environment, it degrades like anything else. Sometimes in cold cases, you don't have great DNA, and it's not a good candidate.
And the testing portion itself is really 10 percent of the process. The rest is everything that comes afterwards: the expertise of genealogists, investigators, crime analysts. Really, good old-fashioned police work. Which Kari can speak to because that's what her agency had to do. It's a good idea to think that genealogy is like any lead that comes into a police agency. That is just the starting point.
KAREN FRIEDMAN: Kari, that leads us right back to you. Tell me a little bit about how you identified Joe Michael Ervin.
KARI JOHNSON: Sure. It's a bit of a story, but I will piggyback off of what Angela said, and I think it really started with just good old-fashioned police work. And I say that about the investigators that responded on these scenes originally. DNA just wasn't a thing in 1978 and 1980 and 1981, and yet they had the forethought to collect great items of evidence that contained DNA.
And then, of course, we have the benefit of people in the lab having the knowledge of grants that Angela and the DOJ and BJA offer. They submitted for those grants, and that brought us to this place of using this new technology. And again, echoing what you said, it is not a quick process.
Two girls in our crime lab took on the task of working the genetic genealogy on this case. Tracy Carlson and Stacy Haff worked the better part of a year and a half, just looking at our matches, which were very low – so it was very difficult – and building out those family lines. It was around March of 2021 that they recognized that the family lines of our unknown offender stemmed from Texas. They had the thought to reach out to Texas Department of Public Safety and ask if they would do a familial search in their state offender database. And Texas DPS agreed.
I actually flew down to Texas in April of 2021 to meet with a woman who was potentially the first cousin of our suspect's mother. She was very cooperative. She had never heard of the woman who was the suspect's mother. We got her DNA. We sent it off to one of the companies Angela mentioned that allow law enforcement searches of DNA. And she came back as not a match at all.
Through all of this there are so many emotional highs and lows, because you think we're on the right track and then you get big goose eggs. It feels like starting all over again. But then, in June of 2021, Texas Department of Public Safety reached out and asked us to join a Zoom meeting. There were 11 participants in that meeting. And we thought, well, if it was bad news, they would just send us a letter. So, we figured it was good news.
What they told us was that they had a potential match to a Texas offender by the name of Paul Ervin. And Paul Ervin was actually a name that was very familiar to Tracy and Stacy as they built out the family lines. We knew Paul had brothers, and we knew it wasn't Paul. Paul couldn't be our suspect, because his DNA profile was in CODIS and it didn't match our offender. So, as they provide information to us from Texas, they give us a list of the family members that Paul had included in his intake paperwork in jail. And it listed his parents, and it listed his brothers, but it listed a brother that we had not heard of. And that brother was Joe Michael Ervin.
We are still on that call when my phone starts dinging. And it's Tracy Carlson from the lab, and she's, like, “I just found a marriage certificate in Colorado for Joe Ervin… I just found a residential address for Joe Ervin in Denver around the time of our murders.” So, we're back at that high, right? We're, like, “Who is this person, and could it be him?”
So, I went back to traditional law enforcement methods. I started running his name through databases but couldn't find a thing on him. So, I reached out on a hunch to our Department of Vital Statistics here in Colorado. We didn't know where Ervin had died. But I thought, well, he had lived in Denver, maybe he died in Denver. And they did in fact send me a death certificate for him which indicated he died in July of 1981 in Adams County, in the jail. And he had committed suicide.
As you'll remember, one of our connected cases is an Adams County case. I was working with a detective up there and called him and I said, "Listen, I doubt you're going to have a 40-year-old suicide report, but would you just look to see?" He called me an hour later, and he said, “Not only do we have it, but it's 20 pages long.” And he said, "You're not going to believe why he was in jail." And that's when we first learned that Joe Michael Ervin was responsible for the shooting death of Aurora Police Officer Debra Sue Corr.
If I could just speak about Debra Sue for a moment. She was a two-year veteran of the Aurora Police Department. She was the first police officer in Aurora to ever be killed in the line of duty. And she happened to be married to a Denver police officer. So these cases, you know, you work them long enough and they become a part of you. You become emotionally connected to these cases. But then to hear that the individual you're looking at is responsible for four murders and killed a fellow law enforcement officer, it's a bit of a gut punch.
That spurred us on to look at Joe even harder. I obtained the Aurora Police file. What we got out of the file is information that Joe Ervin had been arrested in the 1970s in Denver for a series of burglary sex assaults. He would break into homes with a knife and sexually assault the victims. The difference there is those victims survived. In about April of 1970, I think it was, he was found not guilty by reason of insanity and he was sent to the Colorado State Mental Hospital for a period of seven years. But what we also know about Joe Ervin from the file is that he had an outstanding homicide warrant from Texas from 1969. He had shot and killed somebody in Texas, and we think that's when he fled up to Colorado.
We also learned that he had been arrested in June of 1980 for breaking into a woman's home in Denver, kidnapping her at gunpoint, driving her to his home in Denver, and sexually assaulting her there. He had actually been charged with that but was out on bond when he killed our second victim in Denver, Dolores Barajas, in June of 1980; our third victim in Denver, Gwendolyn Harris, in December of 1980; Adams County victim Antoinette Parks in 1981; and then Officer Corr. So through all of this, we're like, “This has to be our guy.”
KAREN FRIEDMAN: Wow. Wow. So, Angela, let me ask you this. Kari and her department are doing all this work. They have identified in their minds that Ervin is the one. But there was still a lot of work left to do. He had been buried with family members in Texas, and to get that DNA, you have to exhume the body. That’s an extremely complex process. So you connected Kari and her team with the Texas Rangers to make this happen. Can you tell me about that?
ANGELA WILLIAMSON: Yes. So, one of my team members who oversees the grant that Kari works under pinged me one day and she’s like, we've got a problem. They're so close to identifying this violent serial offender. And whilst exhumations are complicated, they're also very expensive. Kari and her team were wondering whether they could use their grant money for this. However, grants come with restrictions, and the grant that they had could not cover an exhumation. We knew it was going to be thousands of dollars for their agency to incur. And as much as we all know how important this is, agencies don't always have the resources to fund things like this.
But a light bulb went off in my head. One of our grantees for the National Sexual Assault Kit Initiative (SAKI) Program, which covers rapes and rape homicides, is the Texas Rangers, the Texas Department of Public Safety. And they have a grant for identifying violent serial offenders, whether they've committed rapes or rapes and homicides. I know that they've done a lot of exhumations, that they've worked with exhuming deceased offenders to get case closures. So I was like, "Why not introduce them and see if they’ll be willing to work together?"
I already knew the answer, because the Texas Rangers are amazing. I made the introduction and Kari told them what was going on. And, you know, this is such a compelling investigation. Not only do you have four women who were brutally murdered by this individual, but you have a fallen police officer as well. So, like pretty much everyone in our grantee community, they are always willing to help and roll up their sleeves and go with it. This wasn't even a Texas case. It was a Colorado case. But they very much wanted to help.
KAREN FRIEDMAN: Unlike in TV crime shows, where everything looks so clean and neat, exhuming a body is a very complex process that requires a lot of work. Kari, how difficult was it for you to organize and coordinate this part of the investigation?
KARI JOHNSON: Honestly, the hardest part was sitting back and waiting. That connection that Angela made with us with the Texas Rangers, Lieutenant Gooding there, and then ultimately Lieutenant Bobo and some of the other Rangers that helped, that was crucial. Lieutenant Jason Bobo with the Rangers is the one who did all of the work. He coordinated with the cemetery and the funeral home and the Tarrant County Sheriff's Crime Scene Unit. And he brought onboard Mark Ingraham and John Servello from the University of North Texas. They were the forensic anthropologists that did our exhumation for us. So with him doing all that work, I sat back and bit my fingernails waiting for it all to come together.
KAREN FRIEDMAN: Angela, you oversee many BJA grants that support forensics investigations at law enforcement agencies across this country. This particular investigation was supported by two different BJA grants. Could you tell us a little bit about how that worked?
ANGELA WILLIAMSON: Each of our grant programs has specific allowable activities that are usually guided by the authorizing language, which guides us and how we administer the program. In this situation, there was a grant that got Kari so far, through 90 percent of the investigation, nearly all the way to the end. But they were not able to use that grant to do the exhumation and to tie up the loose ends to finally resolve this case. A simple answer would have been, “Sorry, you can't use grant money for it, try and find it somewhere else.” But that's not how we function.
We have all the grant programs under us for a reason, and one of the reasons is so we can leverage them. It was just a natural solution to see if we could utilize the SAKI grant that the Texas Rangers had to help out in this case. Not only did the grant permit activities like exhumations, but their grant also focused on violent serial offenders in Texas. We knew this individual (Ervin) had spent time in Texas and had quite a history. So it was deemed perfectly allowable. And that's why, for the first time ever, we leveraged two grant programs to get one answer for all these families and a sense of justice for the victims. Even though this offender is deceased, people still need answers. That's what we were pleased to do in this situation.
KAREN FRIEDMAN: Just a few years ago, it would not have been possible to solve these cases and name Joe Michael Ervin as a serial killer. The work that both of you ladies did together, combining this cutting-edge science with sophisticated police work, brought justice to Ervin's victims and their families.
Could just tell our listeners a little bit about how it feels to be part of that? And could you tell us why solving these cold cases is so important? Kari, could you start?
KARI JOHNSON: A lot of people have asked that very question, "What does this feel like?" And there's such a variety of responses I could give and emotions that come attached to them.
The biggest one is telling these families who have waited 40 years, who had given up hope and had thought they would never find answers about what happened to their loved ones. Having those personal conversations with them, it's life changing in so many ways.
And there's other agencies, maybe like Los Angeles or New York or Chicago, where there might be more serial killers. As far as I know, Denver only has the one. Truthfully, I'm grateful I got to be a part of it.
But there are so many more important cases. Utilizing these grants that Angela and BJA awarded us, my partner in the cold case unit just made an arrest on a kidnapping sexual assault using the investigative genealogy grant. So I'm excited about being a part of this generation of investigator where these things are available to us.
And we have people like Angela who are willing to step up and not only support logistically but also say, "This is what this money is good for and what we're going to use it for." It gives an opportunity for agencies across the United States to bring answers to people. And that's exciting.
KAREN FRIEDMAN: Did you yourself get to tell the families that you found the person?
KARI JOHNSON: I did. There was a lot of conversation about who was going to make those calls. A lot of people wanted to be involved. But we all came to the conclusion that that's a very intimate conversation. And to have a room full of people in front of them, in person or on speakerphone, could just really feel awkward. So I made the phone calls to the deceased victims' families.
But one other thing that we did that we all felt very strongly about was our district attorney, Dawn Webber, reached out to all of Joe Ervin's surviving victims so that they wouldn't be surprised by his name in the news again. I think that was as impactful for us as actually speaking to the deceased victims' families.
KAREN FRIEDMAN: So, Angela, same question to you.
ANGELA WILLIAMSON: Cold cases are my passion, and there are two key elements to this investigation. One, it highlights this amazing DNA tool that we have, forensic genetic genealogy. I have been in the DNA arena for almost 20 years now, and this has been the biggest game changer. I cannot tell you the number of investigations that I've been part of over the years where we just sat there going, “We've done everything we can. Unless someone confesses, these families or these victims will never get answers.” And now we have FGG – I'm smiling saying this, because it is so powerful. It is such a game changer, and it is so wonderful to give answers to the families or the victims who do survive these horrendous attacks.
The other thing is that, even though in this case this offender was deceased, you can see from Ervin's, history he never stopped offending. This is what we see time and time again. These people do not stop. They might do a few rapes and then a few rape homicides and then some kidnappings, some armed robberies, drug offenses – you name it. This is why it's so important to never give up on any case.
Yes, Joe Michael Ervin was deceased. There was no prosecution. But in a lot of other cases like this, they're still alive, they're still offending. So it's really critical that we take these cases seriously. We go above and beyond to do what we can to identify these perpetrators, to make sure they can't harm anyone else, and to give those answers to families so that they can have a sense of closure. It will never be closure, but it's something. And overall, we want to make sure that every victim's voice is heard. We are the voice for these victims, which is truly an honor. It's my honor to give people like Kari the resources to do their job and to do this fantastic work.
KAREN FRIEDMAN: Well, Angela, that answer really says it all. We can never forget about the victims or their families.
I want to thank both of you, Angela Williamson and Kari Johnson. I can't tell you how much we appreciate the work that you do. Thank you for sharing this incredible story with us. And thank you, everyone, for joining us today on Justice Today.
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