Again...thank you for your questions!

Q: What prompted Marvin Gaye's father to shoot and kill him?

A: There have been different speculations as to the actual reason of the argument that prompted the shooting on April 1, 1984, but here's the one most say is the truth:
The murder was the inevitable result of a lifelong psychological battle between the two. Each was stubborn in his own way, which led to fights and arguments throughout their lives. Marvin had left the country for three years due to problems with the IRS & drugs and had returned home. Both father and son had their own set of problems: Marvin Sr. was a staunch preacher strongly set in his ways, a heavy drinker and had been out of work for years. Marvin Jr. indulged in as many vices as he could - in particular, drugs and extremely kinky sex romps; he also began collecting guns in the early 80's and had even given his father a .38 caliber Smith & Wesson as a Christmas present in 1983.
On the morning of Sunday, April 1, one day before Marvin's 45th birthday, Marvin Sr. was upset over an insurance policy he'd misplaced; he'd been searching for it since the day before and eventually placed the blame on his wife Alberta. She was with Marvin Jr, talking in his bedroom, when Marvin Sr. began yelling at her from downstairs. Junior came out and started yelling back, basically stating that if he had something to say, get your ass up here and do it face-to-face. Dad rushed upstairs and into Junior's room where Junior told his dad that he'd "had enough of his crap and was gonna mess him up," immediately knocked him down and began kicking him. Mom broke up their fight but it wasn't over as far as dad was concerned; he stumbled to his room, got the gun that Junior had given him for a present just a few months earlier and shot Junior in the chest. That shot was the one that killed Marvin Junior, even though another shot was fired. Marvin Gaye Jr. was pronounced dead at 1:01 p.m. It's ironic in retrospect that father was a man of the cloth and son used to sing in his father's Apostolic church.