A 49-year-old man and his dog were found unresponsive in a running car parked inside a garage, Saturday morning.
Arlington Police responded to a call at a home on King William Drive at about 7:30 a.m.
Investigations found that the man was visiting family and was not allowed to bring his dog inside. Family members told officers the man would go sit with the dog in the car.
The family also told officers the man would normally crack the garage door, but it appears he did not and the garage door was found closed.
Get top local stories in DFW delivered to you every morning. Sign up for NBC DFW's News Headlines newsletter.
There were no signs of foul play and the man likely fell asleep while the car was running, succumbing to carbon monoxide poisoning with his dog, according to police.