Toxicology reports have confirmed that carbon monoxide caused the deaths of four people in a Yerington motel last month.
Yerington police say three of the victims had 70-percent carbon monoxide saturation in their blood when they were found April 16th at the Casino West Motel. A fourth had a saturation of 32-percent.
None of the victims showed signs of drug or alcohol use.
The bodies were discovered after a maintenance man answered a complaint of water leaking into a room below. Investigators had previously said they believed it was carbon monoxide that killed the victims.
Authorities think the lethal fumes came from a malfunctioning swimming pool heater located beneath their room.