In separate developments in recent weeks, Suffolk County District Attorney Rachael Rollins and Middlesex County District Attorney Marian Ryan both said they are setting up cold case units in their respective jurisdictions. Rollins and Ryan have launched these units in an attempt to get to the bottom of multiple real-life murder mysteries — there are nearly 1,000 unsolved homicide cases in Suffolk and more than 120 in Middlesex.

Middlesex County Homicides
Mary Joe Frug was stabbed and hacked to death on Sparks Street in Cambridge the night of April 4, 1991. Her murder is one of the lingering mysteries that Ryan is hoping to solve.

Frug was killed a few weeks after the first Gulf War ended and on the anniversary of Martin Luther King Jr’s assassination. Frug herself was well-known, and state police initially theorized that her notoriety as a feminist legal scholar may have been connected to her death. She was a professor at New England School of Law and her scholarship was controversial. But colleagues dismissed the police theory as implausible, and her case was never solved.

“It is hard enough to lose somebody. It's almost impossible to lose somebody and not really know what happened or who might be responsible. And this office has a long tradition of being able to get to the end of those cases,” said Ryan.

Ryan has hired veteran Middlesex homicide prosecutor Dave Solet to solve the enigmatic endings to hundreds of individual lives cut short, including Frug's. He is working with experienced state and local police as part of a dedicated unit within the prosecutor’s office. Solet also reportedly will be training new investigators.

Ryan, who was re-elected last year to a second term, said advances in DNA analyses may help get to the bottom of cases now that, until recently, seemed unsolvable.

Indeed, this was the case last year, when Middlesex prosecutors announced that they had determined who murdered a woman named Jane Britton on Jan. 7, 1969. Forensic investigators identified the killer as a serial rapist and murderer named Michael Sumpter. Even though Sumpter had died in 2001 from cancer, police used a DNA sample from his biological brother to solve the mystery. Closing the Britton case provided some degree of solace for Britton’s surviving relatives, said Ryan, and it also cleared several men long suspected of raping and killing her.

Some of Ryan's supporters say that she seems to approach murder cases from the perspective of a crime victim, because she was. As a young Middlesex prosecutor years ago, Ryan witnessed the murder of a fellow assistant DA, who also happened to be her boyfriend.

“We were driving back to the Cambridge courthouse one night [and] had car trouble on Memorial Drive. And while we were there we were approached by three individuals, one who attempted to take me out of the car. He was trying to protect me from being pulled out of the car. And at some point the individual on his side of the car opened fire.”

The assailants were identified, and that case was quickly solved. Ryan said she wants to see the same resolution to other homicides in the commonwealth’s largest county.

But Ryan also has been criticized for failing to bring closure to one particular high-profile case; a triple murder on a quiet street in Waltham on September 11, 2011, that the FBI and state police believe to be linked to one of the Boston Marathon bombers, Tamarlan Tsarnaev. Ryan answered her critics this way.

“Do people have a good sense of what might have happened or an idea about who might be responsible?" Ryan asked. "Yes, but that's not enough for us to satisfy our ethical obligations.”

Ryan said she and Solet will be looking hard at this and other cases that have yet to be resolved. She said that she is also reaching out directly to residents of Middlesex County — from Lowell to Belmont — for tips and new leads.

Suffolk County Homicides
The murder of 19-year-old Kenneth Keith Rackley is one of nearly 1,000 unsolved murders that Rollins, elected in November, plans to investigate.

“He was murdered up at Washington Park,” said his grandmother, Faye Rackley of Roxbury. Her grandson was shot to death in the summer of 2010.

“It was like a basketball tournament going on. My niece was there with all the grandkids. And they heard gunshots and everybody took off running and he got hit by a bullet. And so, I hope I live long enough to see it solved. I just pray for that.”

Though Rackley’s killer was never captured, police insist that it was not for a lack of trying. The Boston Police Department’s Cold Case squad and Rollins’ predecessor in the DA’s office, Dan Conley, investigated the case, and even put out a video seeking witnesses, to no avail.

Most media attention since Rollins' election has focused on her list of 15 do-not prosecute crimes. She argues that instead of assistant DAs working overtime to convict petty thieves, shoplifters and opioid users, they should use the hours saved to crack cold cases, like the Rackley murder.

“We're looking at ways [for my almost] 300 employees [to be] committed to unsolved homicides, not just lawyers,” said Rollins, “and then every ADA in the office having an unsolved case that they're responsible for, above and beyond their caseload.”

Rollins’ office has not made an official announcement about the cold case initiative. Even though one or more Suffolk County DA staff members will be working full-time on this project, a spokesperson would not explain how other employees will find the time to focus on hard to crack cases, many dating back to the 1960’s and 70’s.

Rollins and Ryan both say they hope that a dedicated unit under a prosecutor’s direct leadership will yield results for families still left in the dark.

If you have information that could lead to the apprehension of a suspect in an unsolved homicide in Suffolk County please call: call 1-800-494-TIPS or text ‘TIP’ to CRIME.

If you have information that could lead to the apprehension of a suspect in an unsolved homicide in Middlesex County you are encouraged to contact the state police assigned to the District Attorney’s Office at 781-867-6600.