Hamilton County Sheriff's Office investigators are waiting for results from an autopsy to learn if a 53-year-old Ooltewah man was slain at his mother's residence.

Allen David Gibson was found with a head injury just after noon Monday in the residence at 6437 Snow Hill Road, authorities said.

Detectives ruled Gibson's death as "suspicious" pending the outcome of a medical examiner's report. In the meantime, his death is being treated as a homicide and an autopsy was performed Tuesday.

"We're not experts on these things," said Hamilton County Sheriff's Office Chief Deputy Allen Branum when asked about the forensics in the case. "There's just some injuries they couldn't be positive about."

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About eight investigators were outside Gibson's home Tuesday afternoon, continuing to go through the scene and collect evidence.

In recent years, Gibson was arrested on out-of-state warrants and in 2009 was convicted of assault in Chattanooga, according to Hamilton County court records.

In the 1990s, he was charged with attempted murder, but he was convicted on a downgraded charge of aggravated assault, records show. He also was convicted of attempted carjacking in a separate case.

Anyone with any information about Gibson's death is asked to call Hamilton County Sheriff's Office at 209-7000.