ATF Investigates Van Explosion That Injured 3

MONROE (WWJ/AP) - Police are trying to figure out what caused a blast that turned a vehicle along a Monroe street into a blackened shell and seriously injured a man and two children inside.

Authorities are investigating the explosion that happened near the intersection of Elm Avenue and I-75 late Tuesday night. It happened in a wooded area away from any homes or businesses. Windows were blown out and everything in the van burned up. The only thing left was the metal frame.

Police had said incident was "being investigated as the detonation of a car bomb," but later said it could have been the result of a vehicle malfunction or something else.

Police did not publicly identify the three victims or say who owns the vehicle. The Monroe Evening News reported law enforcement officials saying the father, reportedly a divorce attorney from Sylvania, Oh., pulled his sons from the burning vehicle.

Monroe Police Lieutenant Charlie Abel said the case is now in the hands of federal investigators.

"ATF (Bureau of Alcohol Tobacco and Firearms) will be coming in to do further investigations. We'll be assisting them, but the local ATF office out of Ann Arbor will be taking the lead on this investigation," Abel said.

WWJ spoke with Ruth Holly who was nearby when it happened.

"I was fearful that somebody might be in it [the van], and at that time I had no clue if they'd gotten out or not," said Holly. "I really didn't want to go down and see someone burning ... and it was totally engulfed when I looked," she said.

All three passengers were last reported in serious condition at St. Vincent's Hospital in Monroe.

Stay with WWJ and CBSDetroit.com for the latest.

(The Associated Press contributed to this report.)