Ezekiel Elliott's Under Investigation Over Vegas Incident

The criminal investigation into Ezekiel Elliott over his Las Vegas altercation with a security guard is officially underway, TMZ Sports has learned. 

A rep for the Las Vegas Metropolitan Police Dept. tells us ... they were contacted by Kyle Johnson, who claims he was the victim of a battery committed by the NFL star. 

"This incident is under investigation," the spokesperson confirmed. 

We reached out to Zeke's camp and a rep told us, "No comment."

As we previously reported, 19-year-old Johnson has stated he was going to file a police report over the May 19 incident at the Electric Daisy Carnival when Elliott knocked Johnson to the ground during a dispute in the parking lot. 

At the time, police officers working at the event detained the Dallas Cowboys running back and placed him in handcuffs -- but he was NOT arrested because Johnson told them he did not want to press charges. 

At the time, cops described the incident as a "battery" -- since Ezekiel clearly used his body to push Johnson into a metal gate, ultimately knocking him to the ground. 

Johnson publicly demanded a "sincere" apology from Zeke -- and said if he didn't get it, he would explore his legal options. 

Elliott and his reps have accused Johnson of running an extortion scheme -- implying Johnson was more interested in getting money from Zeke than getting justice.