Firefighters discovered the bodies of a man and his mother Sunday in their north Bexar County home.

Authorities believe the victims died of carbon monoxide poisoning after a car was left running inside their garage in the 1900 block of Shoreham since late Saturday night.

“It appears that they slept maybe through the night,” said Sgt. Tammy Burr, of the Bexar County Sheriff’s Department, “or sometime in the middle of the night, and they got up and did not make it out of the house.”

Neighbors said the man pulled into his garage and closed the door with the car running and then ran across the street to show them a new taekwondo medal he had just won. Neighbors said he stayed there talking for several hours.

“He could have inadvertently pulled into the garage for something and forgot to shut it off,” said Bill Cooper, a neighbor.

Firefighters believe the man forgot to shut his car off when he went back into his home.

When firefighters arrived at the home around 5:30 p.m. Sunday, the carbon monoxide levels in the home were at deadly levels.

“Our meters read up to 900 and something,” said John Benavides, of the Bexar-Bulverde Fire Department. “But it was beyond that. It was at about 1000.”

Firefighters were finally able to enter the home around 7:30 p.m.

The names of the victims were not immediately available.