Profile of a Bureau: MCAO’s Cold Case Team

Major Offenders

A cold case is one of the most challenging types of cases for law enforcement to investigate and for the County Attorney’s Office to prosecute. In Arizona, a cold case is defined as “a homicide or a felony sexual offense that remains unsolved for one year or more after being reported to a law enforcement agency and that has no viable and unexplored investigatory leads.” Some cases date back a few years, while other cases went cold decades ago. In 2008, the Arizona state legislature passed a law that requires the retention of cold case biological evidence for 55 years to assist in the effort to bring justice to victims whose cases were not solved.

In 2008, the Maricopa County Attorney’s Office participated in the Solving Cases through DNA Task Force with valley agencies by supplying a detective on a part-time basis. During this time, many local law enforcement agencies were experiencing staffing and funding shortages, so this extra resource was essential to the process. The collaborative process was successful, so MCAO decided to develop an in-house cold case investigation unit.

In July 2012, MCAO established a new section of the Investigations Division, the Violent Crime Bureau. Three detectives were assigned to this bureau with the full-time responsibility of assisting other valley agencies with the investigation of unsolved homicides and sex crimes. Combined, the three detectives assigned to the unit have over 100 years of law enforcement experience, with over 60 years dedicated to investigating sex crimes and homicides. MCAO also houses a Cold Case Bureau within the Major Crimes Division, staffed with three attorneys and a paralegal.

Working a cold case requires detectives to track down victims, witnesses, evidence (police reports, physical evidence and lab results) and the original law enforcement officers on the case. This is often challenging work with all sorts of obstacles. If the case is particularly old, locating persons involved is often difficult. Sometimes key persons have died or their memories are not reliable. Locating evidence can be a challenge and once it’s located, the detectives must work with deputy county attorneys to ensure that it is admissible. Testing physical evidence may depend upon the current workload of the local or state crime lab, which might have other priorities or be short-staffed.

But sometimes persistence pays off and detectives get new leads. This may be the result of new DNA testing that was not available at the time the crime was committed, a new witness comes forward or a suspect will simply confess. Once the case becomes viable, the MCAO detectives work with local law enforcement and a Cold Case Deputy County Attorney to file charges if there is a reasonable likelihood of conviction.

To date, the MCAO Cold Case team has reviewed more than 100 cases, solving 17. The detectives determined that 60 of those cases were not workable because witnesses or evidence was not available. The team is currently reviewing more than a dozen cases.