Victims, possible motive identified in South Dakota triple murder allegedly committed by former mayor

The three shooting victims allegedly killed by a former South Dakota mayor on Memorial Day have been identified, as well as a possible motive.

Court documents obtained by Fox News Digital identified the deceased as 21-year-old Zach Frankus, 26-year-old Paul Frankus and 35-year-old Timothy Richmond. The spat between the three and the former Centerville mayor, Jay Ostrem, 64, was allegedly a result of a sexual assault against Ostrem's wife.

Victim Zach Frankus reported the shooting at 9:44 pm. Monday from a residence in Centerville, telling Lincoln County Sheriff's Office dispatchers that his brother had been shot and killed by a man with a shotgun, and the shooter had returned to his home. Some time later, Zach told the dispatcher that he too had been shot before he stopped speaking.

"You could hear just pop," witness Mark Weets told local TV station KELO. "I think I heard about five rounds go off and so I started kind of peeking out the window and looking around and recording. There were people that were running – running down Main Street here, and one of them surrendered down there about a block down there and gave up, they arrested them."

FORMER SOUTH DAKOTA MAYOR CHARGED IN TRIPLE MURDER

Court documents say Ostrem was seen leaving the home on Main Street by a responding Game, Fish and Parks officer, and that he initially ignored commands to stop before he eventually laid down on the ground. He was allegedly found bleeding from his left hand, smelling of alcohol and with a .380 handgun and an AR-style rifle with spent shotgun shell casings and a spent rifle casing in his possession. 

The three victims were found dead inside the home. 

SIGNATURES SUBMITTED IN BID TO BRING CALIFORNIA-STYLE 'TOP 2' PRIMARIES TO SOUTH DAKOTA

Officers then went to Ostrem's home, and his wife told investigators that she had informed her husband the day of the shooting that she and Paul Frankus had been drinking together on May 23 when he forcibly kissed her and exposed his genitals to her, the court documents say. The news allegedly led to Ostrem "raging out of the house," without saying where he was going. 

Local reports say Ostrem previously served as a city councilor and mayor of Centerville, which is in Turner County. He was also a deputy with the Turner County Sheriff's Office, KELO reported. 

CLICK HERE TO GET THE FOX NEWS APP

South Dakota's Division of Criminal Investigation is leading the triple homicide investigation, with assistance from numerous other local agencies. 

Ostrem is being held in the Minnehaha County Jail. Online court records say he is being held without bond, with a court appearance set for 4 p.m. Wednesday.