BUFFALO, NY-- A Buffalo Police officer is facing charges in connection with a March 18 incident.

The Erie County District Attorney's office says Officer Joseph Hassett is charged with two counts of assault, official misconduct and offering a false instrument for filing.

Investigators say Hassett caused injury to an individual in his custody in a cell block under Buffalo City Court on March 18.

Hassett was arraigned Friday and pleaded not guilty was released on his own recognizance. His arraignment was originally scheduled for Sept. 5, but the defendant asked the court to appear at an earlier date.

Hassett will appear before Judge Joseph A. Fiorella for a pre-trial conference on Sept. 12 at 9:30 a.m.

Details of what happened that day were not released. The victim was treated at ECMC for a head wound.

Erie County District Attorney John Flynn said in a press conference Tuesday afternoon that he, along with other attorneys in the DA's office, say they viewed surveillance video of the incident in May, and that the video is disturbing.

The video was discovered after the victim's attorney requested it in May while investigating his client's case. When asked why the start of an investigation took so long, Buffalo Police Commissioner Daniel Derenda said they never received a complaint. Once they were alerted to the incident, an Internal Affairs investigation was started.

Flynn says they are not releasing the video publicly to avoid tainting a potential jury pool.

Hassett, who is suspended with pay, will be arraigned in City Court on September 5. He's an eight-year veteran of the Buffalo Police Department.

Late Tuesday afternoon, 2 On Your Side received a statement from Hassett's attorney, Timoth Hoover. He said his client's use of forced was "entirely justified" and that Hassett is innocent of these charges.

Hoover's entire statement is below:

"Officer Joseph Hassett is innocent of the misdemeanor allegations that have been filed against him regarding a legal arrest and a proper use of limited force, occurring more than five months ago.

Officer Hassett’s limited use of force was entirely justified to gain control of a physically resistant, aggressive and non-compliant arrestee.

Officer Hassett is a highly decorated, brave and proud police officer, who serves his community with honor and pride. He is the recipient of the BPD’s Medal of Honor, for valor and bravery in the line of duty, awarded after he was shot while apprehending a fleeing suspect in 2013.

We look forward to trying these allegations in court and obtaining a complete acquittal for Officer Hassett."