SAN DIEGO, Cal. (NBC) - Paul Slysh has an idea of why his son, Paul Slysh Jr., lived in a tiny trailer in San Diego, California, under terrible conditions for years.
"I think he must have been 18, 19 something like that, and we discovered he was schizophrenic paranoid," Slysh said.
His son's mental issues often made it easy for people to take advantage of him.
In 2006 Slysh and his son had a falling out.
The two rarely spoke after Paul Junior inherited $2 million from his late mother.
"What happened to all that money? I don't know That's a great mystery, Barbara wouldn't tell me anything," Slysh said.
Barbara Brand, 81, is the woman who Paul Slysh, Sr. said has known his son for about 40 years.
Slysh said the two lived together inside a trailer and had a strange relationship that was like mother and son.
"I understand now, from input I'm getting from a couple people that they may have had a little bit of a romantic relationship," Slysh said.
Homicide investigators said Brand admitted to shooting Paul Junior on July 12 inside their trailer during an argument over her granddaughter.
Police said Brand got upset, took out her deceased husband's gun and shot Slysh.
Neighbors told police they heard several shots.
Officers found Slysh wounded with three gunshot wounds to the stomach.
Hours after the shooting, Paul Senior saw his son for the first time in a long time at the hospital.
"When I asked him, did Barbara shoot you? His shook his head back and forth violently."
Paul Junior died from complications a few days later.
In court Tuesday, Brand pleaded not guilty in court to one count of first degree murder.
Brand's bail has been set at $1 million.