Tear gas grenade thrown by Bernalillo County deputy caused deadly house fire, investigators say

The only possible cause of the fire that killed Brett Rosenau, 15, last month was a grenade thrown by a Bernalillo County Sheriff’s deputy who was a member of the SWAT team that July night, local fire officials said Friday.

The Fire/Arson Investigation Division of Albuquerque Fire Rescue ruled the fire an accident, and discussed preliminary findings during a news conference on Friday.

It is extremely likely that the fire was caused by a Tri-Chamber Flameless Grenade thrown through a front window of the house, said Jason Ramirez, captain of the fire/arson investigation division.

The grenade emits CS gas, commonly known as tear gas.

“So at this time, the classification of that fire is ruled accidental, and we were unable to eliminate that device being an ignition source,” Ramirez told reporters on Friday. “All other ignition sources in the room were eliminated at this point. So that’s where we’re at in the investigation. At this point in our investigation, there is no other possibility in that room of origin, in that area.”

The grenade landed on a mattress behind the window, said Albuquerque Police Commander Kyle Hartsock. Hartsock displayed a video showing the grenade smoking, and the mattress catching fire. The video shows police using a robot to pull the flaming mattress out of the house, but at that point the fire had spread.

Firefighters delayed entering the building because, Albuquerque Police Chief Medina has said, there were concerns Kelley was armed, and he was still inside. It remains unclear if police actually found any weapons on Kelley or in the home.

After Kelley surrendered, firefighters searched the house and found Rosenau’s body inside, Hartsock said.