HEMPFIELD TOWNSHIP (KDKA) — Douglas Novak pleaded guilty, but mentally ill, in court on Friday after being accused of lighting his house on fire to cover up the homicide of his elderly father.

According to police, Novak beat his 92-year-old father, Frank Novak, to death and then set the house on fire in order to cover it up.

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When the incident occurred in January, police did not believe the father died as a result of the house fire.

“There was no evidence that this person would have died from anything would be consistent with a fire,” State Trooper Stephen Limani said in January. “There were bruises, lacerations, broken bones.”

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During the investigation, investigators said that Novak lighted the fire and a neighbor called 911.

The neighbor then approached the home and when they attempted to see if anyone was home, a man they believed to Douglas Novak.

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Novak faces 20-40 years in prison.