BOSTON — Several state troopers in Massachusetts face federal charges for receiving overtime payments for thousands of hours they didn’t work and writing phony traffic citations to say they did.

“Instead of enforcing the rules of the road and cracking down on aggressive drivers, they selfishly lined their pockets with paychecks from bogus shifts at the expense of hard-working taxpayers,” said Harold H. Shaw, special agent in charge of the FBI’s Boston division.

The troopers face federal charges because a portion of their overtime pay was derived from federal transportation funds.

The overtime scandal has rocked the state police, forcing the retirement of some troopers and officers. An internal audit of payroll records disclosed that as many as 46 current and former state troopers may have been involved. Their names were sent to state and federal officials for investigation.

On Wednesday, former State Police Lt. David Wilson, 57, was indicted by a federal grand jury on an embezzlement charge tied to the scandal, according to U.S. Attorney Andrew Lelling’s office.

Wilson retired last year after the accusations came to light that he and other troopers received overtime for hours they did not work as members of the Massachusetts Turnpike Troop E. That troop has since been disbanded.

Wilson is one of six current and former troopers who have been arrested and charged. Two of them have pleaded guilty, agreeing to prison time and paying back the money they received for work they didn’t do.

Wilson received $12,450 for overtime shifts he never worked, according to court documents. To conceal the graft, Wilson falsified traffic citations to make it appear that they were issued during his bogus overtime shifts, federal prosecutors said.

Another retired trooper, Daren DeJong, 56, of Uxbridge, was paid $14,062 in 2016 for hours he didn’t work, prosecutors said.

Colonel Kerry A. Gilpin, who took over the state police last year, said the agency has made several changes in response to the scandal, including requiring troopers to personally show up for roll call during shifts, regular audits of the biggest earners and activating GPS devices installed in police vehicles.

“We owe the public to be transparent and do whatever we can do to show people we are serious about earning back the public trust,” Gilpin said recently.

Christian Wade is the CNHI state reporter for Massachusetts. Contact him at cwade@cnhi.com.