MONROE — No charges are expected in a head-on crash that killed two people on U.S. 2 east of Monroe.

The Snohomish County Medical Examiner’s Office was still working to identify the deceased as of Saturday. Troopers were unable to identify them at the scene.

Just before 1 p.m. Thurdsay, someone was driving a Mercedes-Benz ML350 SUV going west on U.S. 2 when the vehicle went off the road to the right, according to a Washington State Patrol memo. The driver reportedly then overcorrected to the left, crossed over the center line near Sofie Road and crashed head-on into a dump truck going east.

The SUV caught fire. The driver and a passenger inside were killed. A state patrol memo listed their ages, genders and hometowns as unknown.

Troopers shut down the highway in both directions until a little after 8 p.m.

The dump truck driver, 58, of Lake Stevens, was released from EvergreenHealth Monroe with minor injuries. He has been cooperative throughout the investigation, Oliphant said.

In a preliminary investigation, Oliphant said witnesses reported the Mercedes-Benz was moving erratically shortly before the crash. The driver may have been trying to pass in a non-passing section of the road, Oliphant said.

The speed limit is 55 mph on the section of U.S. 2 near Sofie Road. Based on skid marks, troopers believe the dump truck driver hit the brakes and swerved to the right.

It was impossible to tell at the scene if drugs or alcohol were involved, Oliphant said. Usually, troopers can make at least an educated guess, based on whether they see substances in the vehicle, or if they can smell intoxicants.

The SUV was too badly damaged in this case.

“There was not much left inside of the car for us to make that determination at all,” Oliphant said.

Troopers were still waiting for toxicology reports.

The full investigation will likely take a long time, Oliphant said. Months, possibly up to a year. Fatal crashes require more time, and troopers are currently short-staffed, he said.

While no crime is suspected, Oliphant said it’s important to give family a full picture of what happened.

Zachariah Bryan: 425-339-3431; zbryan@heraldnet.com. Twitter: @zachariahtb.