It began as an argument on a bus, police said. Witnesses told authorities Cadesha Bishop was being “argumentative” during the ride, and a 74-year-old man, on his way off the bus, told her to be nice.

Video shows what happened next: Bishop shoved the man off the bus, Las Vegas Metropolitan Police said, through the open door. He landed face down on the sidewalk on top of his collapsed shopping cart.

The man, later identified as Serge Fournier, landed roughly “eight feet from the bus doorway” where he hit his head during the altercation in downtown Las Vegas on March 21, according to the arrest report. Although he refused medical attention at the scene, Fournier arrived at the University Medical Center later that evening, police said.

Fournier died about a month later due to complications from trauma to the torso. On May 3, his family notified detectives of his death, at which point authorities ruled it a homicide.

Bishop, 25, was arrested and charged with murder on May 6. According to the Las Vegas Sun, Bishop was identified partly by a “Love” emblem on her jacket and the Spider-Man backpack her son was carrying. He was allegedly present during the incident.

Police released security camera video of the incident on Monday, asking for more information from witnesses who happened to be there.

Bishop has been convicted twice of misdemeanor domestic battery charges in 2014 and 2015, according to court records. She was held on $100,000 bail. According to the Las Vegas Review-Journal, she was released after posting bond and agreeing to be placed on electronic monitoring.

Read more:

An Army sergeant was charged after road rage battle. She says this video proves she’s the victim.

After cyclist is hit by police car turning right on red, police charge cyclist

A lesson on gun safety ended when a man accidentally shot his 6-year-old daughter, police say