Leath, 33, waited at the bottom of the escalator for Driscoll and the woman, then "set down his backpack and took a fighting stance," police said after reviewing evidence from surveillance cameras, KTNV reports.
Driscoll walked toward Leath, who threw one punch which knocked Driscoll to the ground on his back, police say.
Driscoll did not move after the punch, according to the report. He was transported to a hospital where he died one hour after the attack.
Leath fled the area. Police took him into custody near the Mirage Hotel. He later told police that he remembered being at the pedestrian bridge and being contacted by police but he “offered no explanation of the incident,” WWLP reports.
Driscoll served 22 years with the Connecticut State Police.