In this March 15, 2007 photo, Michael Griffin pinned his badge onto his uniform during a Minneapolis Police Department Academy graduation ceremony in Minneapolis. Jeff Wheeler | Star Tribune file 2007 via AP

A day after he was indicted, Minneapolis Officer Michael Griffin on Thursday pleaded not guilty to multiple federal criminal charges, including use of excessive force and perjury.

Charges unveiled Wednesday allege Griffin assaulted "at least four people while off-duty and after first identifying himself as a police officer," the U.S. Attorney's Office said.

According to the nine-count indictment, Griffin, while off-duty, assaulted people in 2010 and 2011 while he was at bars and restaurants in downtown Minneapolis, kicking and punching people who offered no resistance after he identified himself as an officer.

Documents say Griffin then provided "false, incomplete, and misleading information" to officers arriving on the scene and also falsified records about the encounters and lied to authorities during depositions.

A pre-trial hearing is scheduled for July.

Griffin was already at the center of two police brutality lawsuits that have cost the city more than $400,000. He'd been investigated more than a dozen times but never been disciplined.

Attorney Gregg Corwin, who's represented police officers in labor disputes for more than 40 years, suspects the U.S. Attorney's Office was trying to make a political statement, given the Justice Department's focus on policing in cities like Ferguson, Mo., and Baltimore.

"The timing seems to be suspect as to why — after up to five years have passed — before anyone did anything and all of a sudden they're bring a criminal case against this officer," he said.

A spokesperson for U.S. Attorney Andy Luger denied the national climate had anything to do with the charges against Griffin.

"Police officers cannot use their shield as a weapon against innocent civilians," Luger said in a statement. "This defendant is charged with assaulting at least four people in his capacity as an off-duty officer, filing false paperwork and lying multiple times while under oath."

Griffin is expected to appear in court Thursday to face the charges.

Griffin's attorney, Ryan Kaess, said Griffin "steadfastly maintains his innocence of all charges. He intends to vigorously defend himself against these false accusations and is confident that when all the facts are presented to a jury, he will be found not guilty."

Ron Edwards, spokesperson for the Black Police Officer's Association, suspects Griffin, who is African-American, is partly the victim of a double standard. He said other white officers have been the subject of more expensive lawsuits.

But Edwards, who is also a member of a citizen advisory group working with the Minneapolis Police Department, stopped short of saying the charges against Griffin are racially motivated. He said Griffin had a promising career, but that's probably over.

"We actually in the African-American community can't afford that," he said. "We need as many officers, good officers as we can find. But somewhere he went astray."

The 2010 incident involves a confrontation between Griffin and Ibrahim Regai. Named as "I.R." in the indictment, Regai had filed a civil suit alleging Griffin knocked him out in 2010 following an argument outside a nightclub. Regai sued Griffin and the city, and reached a settlement with the city earlier last year for $140,000.

In 2011, Griffin allegedly assaulted three people outside another downtown night spot while off duty. And like the previous case, he's accused of using excessive force and lying about what happened.

Minneapolis Police Chief Janee Harteau didn't comment directly on the allegations against Griffin but said the department is making progress in identifying and correcting the actions of problem officers.

"Unfortunately, some officers' actions of the past will injure and harm the department today," she added.

In May 2013, Griffin was one of more than a dozen police officers given the Medal of Valor for his response to the mass shooting at Accent Signage in September of 2012. Griffin's public personnel file also contains an Award of Commendation in 2009 after Griffin helped chase down an armed suspect.

Yet during his nearly eight years on the force, Griffin has been the subject of at least 18 investigations by either the Internal Affairs Unit, the city's former Civilian Review Authority or the Office of Police Conduct Review.

Read the indictment: