Upset that his partner of 40 years was planning to leave him, a St. Paul man fatally shot the woman Thursday in front of their grown son.

John Gordon Weisner Jr., 56, was charged Friday in Ramsey County District Court with second-degree murder in the killing of Ramona Turner, 54. Court documents show that the couple had a contentious relationship and fought often.

Weisner was also jealous of Turner's friendship with one his male friends, according to the criminal complaint. The couple, their two sons, a girlfriend of one of the sons and Weisner's male friend had all been drinking at Mounds Park Bar just before the shooting, which occurred about 1:20 a.m. in the family's home in the 100 block of E. 6th Street.

Turner had called the male friend about 1:15 a.m. after she and Weisner arrived home, the complaint said.

"Something just snapped in my head," Weisner allegedly told police of his reaction to the phone call.

According to the complaint:

Weisner and Turner had been dating since they were young teenagers, but never married. Turner had recently informed a neighbor and her sons that she was going to leave Weisner because he treated her poorly.

Weisner's sister told police that he had confided in her about the pending breakup and that he was scared of being on his own and had contemplated suicide.

Weisner's male friend told police that nothing sexual had happened between him and Turner. At the bar, he said, he spoke with both Weisner and Turner, and he and Turner also "engaged in some flirtatious banter." The friend and Turner hugged when Turner and Weisner left.

The couple's son and his girlfriend had gone home earlier and were lying on the living room couch when Turner and Weisner arrived. The son told police that his parents entered the home arguing.

According to the son, Weisner went into a first-floor bedroom, the basement and the bedroom again before entering the living room, pumping a shotgun and confronting Turner: "Alright, [expletive]."

The son heard one gunshot. He jumped up, grabbed the gun and threw it to the side.

"You just [expletive] shot my mom!" the son yelled as his girlfriend fled the home with the shotgun.

Turner was shot once in the right side of her neck.

Weisner yelled for the gun so he could shoot himself, the complaint said, then stabbed himself several times with a knife instead.

Weisner told police that he was angered by Turner's friendship with the other man and that he saw her talking on her phone with him. Weisner said that's when he went to get shotgun shells to load the shotgun.

In 2009, Turner obtained an order for protection against Weisner, writing in her petition that he had been upset with how long she had been grocery shopping, so he poured a beer on her, punched her in the arm, pushed her when she tried to call 911 and grabbed her hair. Weisner pleaded guilty to misdemeanor domestic assault.

Chao Xiong • 612-270-4708

Twitter: @ChaoStrib