A former transit police officer and his two supervisors have been indicted in connection with the beating of a homeless man in Boston last year and an attempt to cover up the crime.

"The conduct alleged in these indictments is unacceptable at every level," Suffolk County District Attorney Rachael Rollins said in a statement Wednesday. "Actions like these undermine the hard work of countless honest, professional police officers and seriously erode trust in law enforcement."

Dorston Bartlett, a now-retired officer for the Massachusetts Bay Transportation Authority Police, is accused of striking a 32-year-old homeless man multiple times with a baton at Ashmont station in the early morning hours of July 27, 2018. After a lengthy investigation by police and prosecutors, a grand jury on Wednesday returned indictments charging Bartlett with assault and battery with a dangerous weapon and violating a person’s civil rights, according to the Suffolk County District Attorney's Office.

The indictments also charge Bartlett with misleading a police officer on suspicion of providing false statements to two Boston cops who responded to the scene later that morning. Bartlett faces another assault and battery charge for allegedly grabbing and pushing the homeless man during the booking process after his arrest, according to the district attorney's office.

The grand jury issued additional indictments charging Bartlett, 65, as well as Sgt. David Finnerty and Sgt. Kenny Orcel, with making a false report as a public officer or employee. Finnerty, 43, and Orcel, 55, were also indicted as accessories after the fact to assault and battery with a dangerous weapon. These charges stem from the alleged collusion among all three to create a false incident report on Bartlett’s encounter with the homeless man in the hours following the alleged assault.

Finnerty was the shift officer in charge and Orcel was the shift patrol supervisor at the time of the alleged incident. Both were placed on administrative leave while Bartlett retired last year during the course of the criminal investigation.

Prosecutors allege that Bartlett arrested the homeless man after beating him and attempted to charge him with assault and battery on a police officer. Finnerty allegedly drafted a report that was submitted by Bartlett and ultimately approved by Orcel.

Later that same morning, a member of the Massachusetts Bay Transportation Authority Police command staff learned of Bartlett's use of force and reviewed a preliminary draft of that report as well as surveillance video from public safety cameras at Ashmont station. He then ordered the victim be released from custody without charges, and the criminal investigation was subsequently launched, according to the district attorney's office.

“Words cannot express the extreme disappointment I have in the officers who violated the victim’s and the public’s trust in such an egregious manner,” Massachusetts Bay Transportation Authority Police Chief Kenneth Green said in a statement Wednesday. "However, I refuse to allow the corrupt actions of these individuals to tarnish the vast majority of the men and women of the Transit Police who day in and day out wear their badges and perform their duties with honor and integrity."