UPDATE: New video was sent to 13 Action News showing the moments before the Lateral Vascular Neck Restraint was used on Tashii Brown.
A person close to Brown confirmed it was the 40-year-old in the video.
The video stops before the officers used the neck restraint that left Brown unconscious.
Police are expected to release more video of the confrontation at a breifing on Wednesday.
PREVIOUS STORY: The American Civil Liberties Union of Nevada is calling on Las Vegas Metropolitan Police to stop using a controversial restraint technique.
The call for review comes after a man died Sunday when police used what is commonly called a "chokehold" to take him down.
Las Vegas police say 40-year-old Tashii Brown was behaving erratically when they encountered him outside The Venetian Sunday.
They used a Taser and when that didn't work officers used what is called the lateral vascular neck restraint technique, which is a trademarked law enforcement technique. While officers don't call it a chokehold, Tod Story, executive director of ACLU of Nevada, says the result is the same.
"I'm saying it's all the same thing," said Story. "You're choking them. You are cutting off the supply of either air or blood."
Chokeholds have been banned by several police departments including New York and Los Angeles.
The 2014 death of Eric Garner put the practice under the microscope again when cell phone video captured him telling officers, " I can't breathe" moments before he died. Brown's cause of death has not been determined, but the ACLU says there are too many unanswered questions in the case.
"The individual wasn't armed," Story said. "He wasn't threatening anyone. He may have been acting erratically, but acting erratic should not result in your death."