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Award Information

Award #
Funding Category
Competitive Discretionary
Awardee County
Congressional District
Funding First Awarded
Total funding (to date)

Description of original award (Fiscal Year 2021, $535,000)

MCAO Cold Case Homicide DNA Program

BJA F21 Prosecuting Cold Cases Using DNA O-BJA-2021-94004



Maricopa County Attorney’s Office (MCAO) is one of the nation’s largest public prosecution agencies serving over 4.4 million residents. MCAO works with more than 25 different law enforcement agencies (LEAs) to prosecute crimes committed within Maricopa County. Cold case homicide prosecutions are currently handled by two prosecutors, three investigators, and a paralegal. The prosecutors are experts in DNA evidence. MCAO was the first prosecutor’s office in the country to file homicide charges based on publicly available DNA (forensic genealogy). The investigators have over 63 years of combined experience in law enforcement and homicide investigative work.


The MCAO Cold Case Homicide DNA proposal is a three-year project to increase the time available to devote to cold case homicide investigations through overtime for existing investigators and the hiring of an additional resource, a cold case analyst,  to assist in those investigations. Devoting resources at this level will expedite and ultimately lead to the identification of suspects and increase the number of homicides brought forward for prosecution thus lowering the number of unsolved cold case homicides within Maricopa County.


In early 2020, more than 30% of Maricopa County LEAs and public DNA testing laboratories responded to MCAO’s request for the number of cold case homicides within the county with suspect DNA either in CODIS without a match or available in evidence (mixtures and single sources). This informal request identified more than 340 cold case homicides with suspect DNA, 18 of which are currently under investigation by MCAO cold case detectives.  While an exact number of unresolved Part 1 violent crimes in Maricopa County is unknown, law enforcement and public lab information estimate the number to be around 4,000.


The goal to complete a more comprehensive inventory has been put on hold by lack of staff/resources within the labs and LEAs and the restrictions resulting from COVID19. To fully understand the scope of unsolved homicides within the county, MCAO will utilize interns to assist MCAO, LEAs, and the public testing labs in completing a comprehensive inventory.


MCAO will track and enter applicable information into the FBI’s ViCAP database and/or NamUs, as well as providing grant-required data to BJA. With MCAO leading this collaborative grant project between LEAs and public labs, the number of cold cases awaiting prosecution with suspect DNA will decrease.

Date Created: December 17, 2021