Who is to Blame?

Dateline Dickson City- Last night, one of the strangest murders that ever occurred in the history of this small , NEPA town took place. But first, you need to know the backstory to this unfortunate accident.
Thomas Darrita, a convicted wife beater, was out of of prison after spending twenty years there for beating his wife. He got married to his second wife in the summer of '70. He was trying to reform, and his wife, Harriet Darrita, said that he was the kindest, gentlest, most loving man she had ever known.
Harriet was Thomas' wife for eighteen years last June. She knew about his past, and truly believed that he was a changed man. Although he never actually beat her, he would usually threaten her with an unloaded handgun when he was drunk. He would wave it in her general direction and say "One of these days, Alice. One of these days." No one knows why he called her Alice.
His son, Thomas Darrita Jr., had been a high honor's student at Scranton Prep. He never went to college. He had moved out at sixteen because he didn't like his father's past, and wanted to distance himself from him. He did, however visithis mother regularly, and would sometimes walk in on his parents fighting.
On the night in question, Thomas Darrita was more drunk than usual. He aimed the gun at Harriet, and pulled the trigger. The issuing blast caught both Thomas and Harriet by surprise. Thomas, however, had taken hasty aim, and the shot didn't hit Harriet. It went through the window of their seventh floor apartment, and embedded itself in the heart of the man from the apartment above, who was jumping out of his to commit suicide. It killed him instantly. The name of the man in the apartment above- Thomas Darrita Jr.
But wait, the plot thickens. Apparently, Thomas Jr. had loaded the gun, and then put it back to use on his fahter next time he visited. Thomas Sr. didn't know that the gun was loaded.
So, is it murder, commited by Thomas Sr., or suicide on the part of Thomas Jr.? The courts have yet to decide, but, as Chirs Lobbo, Dickson City Chief of Police, "This is truly the most unusual case I have ever had to investigate.
Thomas is currently on house arrest, awaiting the ruling.