Thomas Driscoll, 57, was walking across a street bridge around 4 a.m. with a female when Brandon Marcus Leath, 33, started shouting at them and following them.
Leath waited for them at the bottom of an escalator then allegedly punched Driscoll, causing him to fall to the ground unconscious.
Driscoll was pronounced dead at a Las Vegas hospital shortly after the attack with head and neck injuries.
He worked for the Connecticut State Police for 22 years before retiring in 2009, spending most of his career on patrol in Hartford and North Canaan.
“It saddens us to hear that he died after being assaulted,” a spokesperson for the Connecticut State Police told Fox News. “Our thoughts and prayers go out to his family and friends.
Leath fled the scene but was apprehended by officers and is now facing a murder charge.
Two Las Vegas men who knew Leath described him as a “ticking time bomb” to FOX5, saying that they tried to have him arrested multiple times.
“He knocked me out so now I have to see a doctor about my possible concussion,” one of the men told the local news outlet.
The Associated Press contributed to this report.