A passing motorist found a body in the trunk of a car parked in a ditch in northeast Houston, Texas, The Houston Chronicle reported.

According to the newspaper, the man's body was found at about 4 a.m. Monday, when a motorist traveling with a woman and a baby spotted the car running with the windshield wipers on.

After the motorist took the keys out of the ignition, he opened the trunk and found the body, The Chronicle reported.

According to Click2Houston.com, police said the motorist was trying to steal the car's speakers when he discovered the body. The dead man appears to be in his 20s or 30s, police said.

"At closer inspection, the citizen discovered there was a man who was dead in the trunk of the car," Jack Harvery of the Houston Police Department told Click2Houston. "At this time, it is not apparent what caused the death of this man. However, given the circumstances of the death and the fact he is in the trunk of the car, it appears to be unnatural."

The investigation is ongoing.

More content from NBCNews.com:

• 'Too holy' for sex? The problem of a married Jesus
• Looking for something to steal, man finds body in trunk
• Video: Good Samaritans tackle alleged gunman in Seattle
• Los Angeles preps for 'Carmageddon II'
• Tree trimmer crushed to death by palm fronds

Follow US News from NBCNews.com on Twitter and Facebook