A total of 14 current and former Springfield police officers now face charges in an attack on a group of civilians that followed a barroom argument almost four years ago.

The new charges announced Wednesday by state Attorney General Maura Healey's office and the FBI's Boston office involve an altercation outside Nathan Bill's bar on April 8, 2015, and accusations that there was a subsequent attempt to cover it up.

Six of the officers had previously been charged with assault and battery. Another seven current officers, one former officer and a bar manager were charged Wednesday with misleading investigators, filing false police reports and perjury.

Investigators say the off-duty officers had a dispute with four other bar patrons. Authorities say the officers later attacked the men in a nearby parking lot. The bar owner was also charged.

Lawyers for several of the officers previously charged said their clients were innocent.

Springfield Mayor Domenic Sarno said he and Acting Commissioner Cheryl Clapprood would continue to "root out" bad police officers.

"Needless to say, this is not a good day for our Springfield Police Department," Sarno said in a statement. "Police officers are held to a higher standard."

All officers will be placed on unpaid suspension, according to Marian Sullivan, Sarno's spokeswoman.

Last year, Springfield agreed to pay $885,000 to settle federal civil rights lawsuits brought by the victims in the attack.

Healey's office has said the victims sustained significant injuries from the attack and that a number of the officers had used weapons.