A 23-year-old Florida man was charged with murder after he allegedly stabbed his grandmother to death while she was in the bathtub, MyFoxTampaBay reports.

Detectives from the Polk County Sheriff’s Office told MyFoxTampaBay Christopher Chase Whaley decided to kill his grandmother, 69-year-old Barbara Denmark, and his aunt, Cassandra Pippin, after reportedly arguing with them.

Whaley allegedly returned Sunday to the home he had lived in with Denmark for the past five years, and attacked his grandmother while she was taking a bath, stabbing her multiple times. He then called police, and turned himself in.

Authorities say they are not sure why Whaley ultimately decided to not kill Pippin. He faces charges of first degree murder.

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