Law enforcement in Iowa suspects three Twin Cities men were murdered after the driver was shot and his two passengers suffered fatal injuries when their car then hit a semitrailer truck head-on, according to newly filed court records in Minnesota.

However, a key mystery prevails: Investigators say they have yet to find evidence that the shot was fired either inside or outside the vehicle.

The shooting and crash occurred in the early morning hours of Oct. 13 along Hwy. 20 near Mason City, the Iowa Department of Criminal Investigation (DCI) said in a statement issued Wednesday afternoon.

The DCI identified the men as driver Tijuan Devell White, 50, of Robbinsdale; and passengers Tyrese Devell Johnson, 21, of Minneapolis; and 38-year-old Augustine T. Monboe, also of Robbinsdale. A relative told an investigator that Johnson is White's son.

White was heading east on Hwy. 20 when he was shot just before the car crossed the median and struck the big rig in the westbound lanes, the Iowa State Patrol said. Flames engulfed both vehicles, and the three men were declared dead at the scene. The trucker was slightly injured.

As of Tuesday's filing of the affidavit, the document read, the Iowa Office of the State Medical Examiner "has a pending and preliminary manner of death as murder cause by the gunshot wound and blunt force trauma for White. The office has a pending and preliminary manner of death as murder caused by blunt force trauma for Tyrese Johnson and Augustine Monboe."

What the DCI, the patrol and a search warrant affidavit filed Tuesday in Hennepin County District Court leave unresolved is the origin of the small-caliber bullet that hit White and remained in his body as he drove on the highway about 30 miles west of Dubuque.

An affidavit that cleared the way for a judge to allow the Minnesota Bureau of Criminal Apprehension to search the assisted-living residence where White and Monboe lived pointed out that "no gunshot holes were noted in the vehicle. No guns, [discharged cartridge] casings or ammunition were recovered from the vehicle." The filing also determined that the location and angle of White's gunshot wound to his left side near his armpit was "counterintuitive to suicide."

The DCI's statement only addressed that "no evidence was located that indicated the gunshot came from outside White's vehicle."

DCI Special Agent Michael Krapfltold the Minnesota Star Tribune that no arrests have been made in connection with the shooting, and "it's possible charges could come about in this case."

Krapfl added that his agency has yet to narrow down the origin of the gunfire in part because "the car was completely burned up, so we may never know what happened inside that car."

According to the affidavit:

About four hours before the crash, an Iowa State Patrol trooper pulled over White for speeding more than 90 miles per hour near Mason City. The trooper saw marijuana in the car and searched the vehicle. He found nothing else suspicious, including no guns, and sent them on their way.

It was around 3:30 a.m., when White "for an indeterminate reason" began hitting the brakes while heading east on Hwy. 20 near the Earlville exit.

After being shot, White' car swerved across the median and continued for another mile in the westbound lane before hitting the semi head-on. Flames engulfed both vehicles.