LAS VEGAS — A Las Vegas police officer used a stun gun seven times and a mixed martial arts chokehold to subdue an unarmed man who died after a foot chase in a casino, authorities said.

Officer Kenneth Lopera thought the man had tried to carjack a pickup truck with two people inside before the officer fired the stun gun and used the chokehold — a tactic that is not approved by the department — Sunday at The Venetian resort, Clark County Undersheriff Kevin McMahill said.

McMahill showed video from Lopera’s body camera during a news conference on the incident. Police posted video of the news conference including edited body camera and Venetian security footage to the Internet.

Lopera is white, and Brown is black. Sheriff Joe Lombardo said there was no indication that race played a role in the incident.

Brown’s cause of death has not been determined and an investigation is ongoing.

McMahill said Lopera was heard saying he used a ‘‘rear naked choke,’’ a mixed martial arts chokehold that differs from a department-approved technique that some departments call a ‘‘lateral vascular neck restraint’’ and others refer to as a carotid artery hold.

Department officials said previously that the officer had used the approved technique, which is banned in many other cities.

McMahill said Lopera held Brown’s neck for more than a minute — far longer than the seven to 10 seconds it might take for an approved carotid restraint to render a person unconscious.

The police official said also that the driver of the pickup didn’t think Brown was trying to carjack his vehicle, and that Brown was not believed to have committed any crime.