NASHVILLE, Tenn. (AP) — A medical examiner has concluded that a Nashville restaurant owner died of accidental suffocation by carbon dioxide inhalation when he was trapped in a cooler.

After an autopsy, the medical examiner said Tuesday that 47-year-old Jay Luther would have been overcome within just a few minutes of entering the Germantown Cafe East cooler Sunday night. The cooler contained dry ice due to a power outage over the weekend. Dry ice dissipates into carbon dioxide gas.

Police said Luther went into the cooler and the door shut, trapping him inside. The interior door release was broken, and Luther was not carrying a cell phone. He was the only person at the business at the time.

His body was found Monday.

Police responded to an alarm at the restaurant Sunday night, but determined it was a false alarm without entering the building because all the lights were out. Investigators think Luther triggered the alarm from inside the cooler in an attempt to save himself.

Police say they are reviewing their policies after leaving the scene without entering the restaurant.

Police said carbon dioxide vapor can displace oxygen in confined spaces.