Police are trying to determine if a 45-year-old man found dead in his St. Louis County home was attacked and killed by one or both of his pit bulls.

St. Louis County police were called to the home near Spanish Lake about 10:30 a.m. Monday. The victim was found dead and had bite marks on his body. His name has not been released.

Relatives found two pit bulls in the home, one of them was acting aggressively. Police say the aggressive dog could not be controlled and had to be fatally shot by an officer. The other pit bull was calm and taken in for evaluation.

The cause of death has not been determined. It wasn't clear if the man was bitten before or after he died.

Chris Johnson, ThinkStock