The suspect, Keith Mauga, is already serving time in prison for a separate aggravated battery.

TAMPA, Fla. -- Investigators say manslaughter charges have been filed against the suspect in the death of notable Tampa muralist Matt Callahan.

The suspect, 34-year-old Keith Mauga, is already serving five years in prison for a separate aggravated battery in St. Petersburg.

Police found Callahan, 40, with a head injury outside the Warehouse Liquor Store and Bar on Gandy Boulevard in Tampa around 3 a.m. on April 11. Callahan died two days later at Tampa General Hospital, leaving behind a wife and a 5-year-old.

A report from the Hillsborough County Sheriff's Office offers details from witnesses about what allegedly happened that night.

Investigators say witnesses saw Callahan approach Mauga multiple times at the bar to apologize for an unknown incident. Witnesses told deputies that a few minutes after they got Callahan to leave Mauga alone and leave the bar, Mauga came outside.

An argument ensued, investigators said, and Mauga allegedly punched Callahan, who fell and was then taken to the hospital. Investigators say Callahan was unconscious after he was punched and never regained consciousness.

The affidavit also says an autopsy was done on Callahan, and the medical examiner ruled Callahan died from severe brain injuries from the punch and the fall.

In May, Callahan's father and The Lure restaurant offered an $8,000 reward for information leading to an arrest in the case. Matt had previously painted a mural inside The Lure.

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