Bismarck police investigated three aggravated assaults over the weekend, but suspects in two of the incidents could not be located.

In the other incident, a 16-year-old Lincoln boy was arrested and cited with aggravated assault. The boy is accused of attempting to strangle his father, a 44-year-old Bismarck man, by putting him in a headlock, Lt. Randy Ziegler said. The assault was reported at 7:58 p.m. Saturday.

The boy was released to the custody of his mother, who lives in Lincoln, Ziegler said.

n Police are looking for a 33-year-old Bismarck man who is the suspect in an aggravated assault that occurred Friday at the South Central High School graduation, Ziegler said.

An 18-year-old man was at the Belle Mehus Auditorium for his girlfriend's graduation and was confronted by the 33-year-old stepfather of his ex-girlfriend. He said the 33-year-old man pushed him against the wall and attempted to strangle him for 30 or 40 seconds, Ziegler said. He said witnesses corroborated the 18-year-old's story, but officers could not locate the 33-year-old man.

The report, called in at 6:46 p.m. Friday, will be sent to the state's attorney's office for possible charges.

n Police also are looking for a 44-year-old Bismarck man who is accused of attempting to strangle his 35-year-old girlfriend, Ziegler said. He said the woman called police at 4:56 a.m. Saturday. She said they had returned to her home after going out for her birthday, and he assaulted her when she refused to have sex with him, Ziegler said.

The man had fled the home before police arrived, he said. A report will be sent to the state's attorney's office.

(Reach reporter Jenny Michael at 250-8225 or jenny.michael@;bismarcktribune.com.)