PORTLAND, Ore. (KOIN) – Using a wheelchair for mobility issues, a 54-year-old man appeared in Multnomah County Circuit Court on Monday and pleaded not guilty to an allegation of murder.

Shawn Kevin McGinnis is charged with being a felon in possession of a firearm, unlawful use of a weapon and murder.

Portland Police arrested him on November 13 in the 300 block of SE 45th Avenue. After his arrest, detectives learned that McGinnis had a “pre-existing injury” that required medical attention.

Police have not specified the nature of the injury.

McGinnis was taken to an area hospital where he received medical treatment. He was released on Friday Nov. 17 and booked into jail.

The investigation started on Nov. 10 when officers were dispatched to a home in the 8100 block of Southeast Glenwood Street on the report of gunfire that occurred approximately 15 minutes prior to the 9-1-1 call.

Officers found 52-year-old Robert Lee Kaiser near a residence and determined that he had died as a result of a gunshot.

According to jail records, McGinnis has been convicted of 10 felonies and 2 misdemeanors throughout his lifetime. His criminal record spans state and federal court in Oregon. McGinnis appears to have been born in New Jersey.

Police have not released specific details about the case, including a potential motive. An affidavit that accompanied an arrest warrant has been sealed.

Anyone with information on the case is asked to contact Detective Anthony Merrill at 503-823-4033, anthony.merrill@portlandoregon.gov.