The number of former Massachusetts State Police troopers receiving pension payments, amid an alleged overtime abuse scandal that has shaken the law enforcement agency, has grown to six.

Eight current and former troopers have been hit with federal and state charges related to the investigation into overtime abuse within the state law enforcement agency. Dozens more remain under investigation as state prosecutors say more indictments are coming.

The total amount for the six who retired and now receive pension payments comes to nearly $44,000 a month. The payments started earlier this year.

Two troopers who are among the charged have been suspended from their jobs and haven't retired.

Pensions are based on base salaries, not overtime or detail work. And while officials like Gov. Charlie Baker have called on the accused troopers to lose their pensions due to the alleged overtime abuse, but there's not a simple process for that to happen.

The amount of money the state retirement board, which handles their pensions, can stop from going out, or even claw back from public employees, remains a complicated legal issue. The board can't take action on benefits until the employee has been convicted of a crime related to their job.

Three former lieutenants who worked as supervisors were indicted by Suffolk County grand jury, Attorney General Maura Healey's office said this week.

One of them, former Lt. David Wilson, is also facing a federal-level charge in the overtime abuse scandal. A 57-year-old Charlton man, Wilson pleaded not guilty to the federal charge of embezzlement and hasn't yet been arraigned on the state charges.

Wilson is receiving a monthly pension payment of $8,791.02.

The other two indicted by the Suffolk County grand jury are 68-year-old John Giulino of Lanesborough, who is receiving $7,465.20, and 52-year-old David Keefe of Norfolk, who is receiving $8,605.05.

The former troopers who were charged at the federal level include 47-year-old Gregory Raftery of Westwood, 50-year-old Paul Cesan of Southwick and 56-year-old Daren Dejong.

Raftery is receiving $6,017.07 a month; Cesan sees a $6,639.43 payment; and Dejong gets $6,251.99.

The two troopers who are suspended and face a federal charge are 45-year-old Gary Herman of Chester and 40-year-old Kevin Sweeney of Braintree.

Raftery and Sweeney have pleaded guilty and Herman has agreed to do so, federal prosecutors say.

In the case of Raftery, the retirement board remains in a holding pattern since he hasn't yet been sentenced.

For the retirement board, the next step after sentencing is sending a notice and acknowledging that the accused person has a right to an administrative hearing.

Everything that a public employee paid into their pension, they can keep, but the board can take away the state's portion, as well as fringe benefits.

After the administrative hearing, the board would make a decision on the forfeiture of the pension.

State statute calls for uniformed members of the State Police to serve a minimum of 20 years in order to receive benefits. The benefits come to 60 percent of the average annual rate of regular compensation in the 12 months before they retire.

The maximum benefit is 75 percent of the last 12 months' salary, available after 25 years of service within a department.