Indictments against at least 10 more Massachusetts State Police troopers accused of stealing overtime money by writing phony tickets and skipping shifts are expected in the near future, MassLive has learned.

A source told MassLive at least 10 more troopers will be indicted. This is in addition to the four troopers already facing federal charges.

It was announced this week that Trooper Gregory Raftery entered a plea deal in federal court in connection with the overtime pay investigation. The trooper retired as the scandal unfolded.

Raftery is one of four troopers charged in U.S. District Court with stealing funds through two specialized state police patrols on the Massachusetts Turnpike and Metropolitan Tunnel system.

Raftery, a 47-year-old Westwood resident, pleaded guilty to one count of embezzling money from a state agency receiving federal funds. He received $54,000 in overtime pay for shifts he did not work in 2015 and 2016, federal prosecutors said.

His admission appears to be the first time a trooper admitted to stealing cash through overtime shifts in 2015. The investigation, which led to the suspension and resignation of more than 40 troopers, focused on 2016.

Raftery must repay $51,337, according to the proposed plea deal.

State police said overtime shifts worked by Troop E in 2015 are being audited. Troop E, which was dissolved during the scandal, was the only troop that could work the Accident Injury Reduction Effort (AIRE) patrols, which were four-hour overtime shifts designed to reduce crashes on the Pike, and X-Team patrols targeting aggressive driving.

Troopers Gary Herman, 45, of Chester; Paul Cesan, 50, of Southwick; and Lt. David Wilson, 57, of Charlton were also charged recently for allegedly embezzling funds. All entered pleas of not guilty.

These four troopers won't be the only ones facing charges. A source told MassLive this week at least 10 more troopers will be facing federal charges. The source expected the charges to be lodged against the troopers in the near future.

Several members of the now-defunct Troop E, some who resigned, are accused of skipping overtime patrols, cutting hours and writing "ghost tickets." The tickets were part of the way troopers covered up the scam, authorities said.

Federal investigators reviewed state Registry of Motor Vehicles records and cruiser radio transmission data to uncover the fraud, federal records said.