A man and a dog found in a vehicle Saturday likely died because of carbon monoxide poisoning, according to the Arlington Police Department.

At around 7:30 a.m. Saturday, officers responded to a home in the 6100 block of King William Drive to investigate after a 49-year-old man and his dog were found unresponsive inside a running car that was parked in the garage.

The man and the dog were pronounced dead at the scene, according to police.

Officers learned the man was visiting family at the home, but was not allowed to bring his dog inside the house. Family members told officers the man would often go out to the car to sit with his dog and would normally open the garage door.

The garage door was closed when officers arrived, police said. There were no signs of foul play, they said.

Investigators think the man likely fell asleep in the car while it was running and both he and the dog succumbed to carbon monoxide poisoning.

The Tarrant County Medical Examiner’s Office will release the identity of the man and determine an official cause and manner of death.