Police reports of the incident state that he was pushed off "with enough force that he never touched any of the steps on the bus" and that "his head landed approximately eight feet from the bus doorway".
Cadesha Bishop, 25, is charged with the murder of 74-year-old Serge Fournier.
She's facing a charge of open murder on an elderly-vulnerable person. Fournier, while holding his walker, falls flat on his face, hitting his head on the sidewalk.
Fournier went to the hospital suffering from multiple injuries after the attack, officials said.
In a Tuesday tweet, Vegas cops stated detectives are still looking to talk with witnesses.
Taylor asserted that Fournier was a "wonderful person" and shared that he would never forget his friend.
Witnesses told police that Bishop, who was with her young son, had been swearing at people on the bus when Fournier told her to "be nicer to passengers".
"No matter what his age, she should not have done that".
A preliminary hearing for her is scheduled for May 21.
His neighbour Trevor Taylor paid tribute to the victim, telling KSNV: "He was an excellent neighbour".
Mr Fournier leaves behind a wife who is disabled.
After the alleged shoving, Bishop reportedly fled the scene. Police said he was bleeding from the head when he was found.
Court records show that Bishop was convicted twice, in 2014 and 2015, of misdemeanor domestic battery charges.