A Massachusetts State Police trooper has admitted receiving free guns from a state-contracted firearms dealer and is cooperating with prosecutors in an ongoing criminal investigation into the sale of department weapons, according to the Boston Globe.

Trooper Robert Outwater testified before a state grand jury investigating allegations of wrongdoing involving at least two former troopers who worked alongside Outwater in the armorer's unit, the Globe said.

The three troopers are accused of selling about 500 used State Police guns to a Greenfield firearms dealer in 2015 on behalf of the department. The troopers allegedly received nearly two dozen of those weapons as personal gifts, the Globe reported.

No charges have been filed.