BOSTON – Guns that are used to protect the public are ending up on the other side of the law. 

Records from the federal Bureau of Alcohol, Tobacco, Firearms show that over 16 years, more than 52,000 guns once owned by law enforcement later showed up at crime scenes. That means roughly 3,000 times a year, a police gun was used in the commission of a crime, sometimes with deadly results. WBZ-TV’s I-Team worked with CBS News in a partnership with non-profit newsrooms “The Trace” and “Reveal” on a special investigation into where old police weapons end up.

Boston mom Ruth Rollins wants to know. Her son Danny was shot and killed when he was 21.

“There were two young men, they were young teenagers that had something to do with my son’s murder, never left their housing development. I wanted to understand how these guns were ending up in our community,” said Rollins, who has since become an anti-gun violence advocate.

Guns sold legally

She was surprised to learn that most often, guns used in crimes originate from a legal transaction.

“Somebody buys guns legally and sells them to somebody that’s not able to purchase them legally, and it’s a business,” Rollins told WBZ.

Stopping guns from falling into the wrong hands is the inspiration behind police sponsored gun buybacks. It’s a subject Boston Police Commissioner Michael Cox speaks about passionately. 

“We’re doing all we can to take as many off the streets,” he has said. But gun control advocates say what police do with their own guns works against that goal.

Massachusetts police sell or trade in guns 

In collaboration with CBS News, the I-Team obtained records showing Massachusetts police departments typically and legally sell back or trade in their service weapons to dealers when they’re no longer of use to officers. This includes Massachusetts State Police, Worcester Police, and others. 

Records show since 2000, Quincy Police traded 200 guns back to a dealer. Cambridge Police sold back 575 guns. Lynn Police sold back 205 and Lawrence Police sold back at least 140. 

Over the border in Nashua, New Hampshire, records show, in the last couple decades, police sold at least 485 guns to eight different dealers across the country.

Records show Boston Police traded in 500 Glock 22 pistols three years ago. A spokesperson said it’s an effort “to reduce the cost to the city. Such transactions usually occur with the licensed firearm wholesalers that we are purchasing the new items from.”

But records from police departments across the country show some have sold guns to dealers even when they’re not buying replacements from them.

The cost of destroying old police guns

“That’s appalling. Those guns, they should not have been sold back to gun dealers. They needed to be destroyed,” Rollins told WBZ. 

Boston Police invited her to watch how they shred guns they’ve confiscated. She thinks old police guns should meet the same fate. One community on Cape Cod is already doing just that. 

“This is a step ahead, this is a victory,” said Tom Stone of the Falmouth Gun Safety Coalition. The group has spent years pushing for local police to destroy officers’ old guns. In April, the coalition finally got what it wanted. The town manager agreed to turn over 26 guns for Massachusetts State Police to destroy.

“My concern obviously is for the safety of Falmouth residents and visitors who come here,” Town Manager Mike Renshaw told WBZ. “We took steps to ensure that there was no possibility of any gun violence incident arising out of these 26 shotguns.”

That comes at a cost. In this case, Falmouth Police Chief Jeffrey Lourie said he could have saved more than $4,000 by selling the guns back. 

“I just feel as a department head that I have a responsibility to the taxpayers,” he said.

Trade-in value for a donation

Falmouth Police have 70 additional guns worth as much as $20,000 they plan to get rid of later this year. Renshaw said he hasn’t decided yet whether to trade them in or destroy them. The select board enacted a new policy to publicly post the trade-in value of weapons when police replace them. If someone donates that amount, police can destroy the guns. 

“It makes me feel good to know that we’re kind of on that leading edge,” said Renshaw.