EVERETT — A Granite Falls woman involved in a multi-vehicle collision that injured eight people and shut down U.S. 2 Monday night is being investigated for vehicular assault.

A judge on Tuesday set bail at $100,000 for Heather M. Lee, 26, who appeared in court in a wheelchair with a heavily bandaged leg.

The Washington State Patrol is investigating whether Lee, 26, was under the influence of marijuana when the crash occurred. Troopers reported finding a marijuana pipe in her 2002 Dodge Durango. She allegedly told a trooper that she had smoked “a bowl” earlier in the day and also was distracted by her young children squabbling in the backseat just before the crash.

The five-vehicle pileup east of Monroe left a 10-year-old boy in another car with a crushed skull, according to court papers. He was taken to Providence Regional Medical Center Everett before being transported to Harborview Medical Center in Seattle, where he was reported in critical condition.

Two others — a woman, 37, and a boy, 13 — were flown to Harborview. The woman was listed Tuesday in satisfactory condition, a hospital spokeswoman said. No further information was available about the teen. The woman and the two boys were from Startup.

The crash was reported about 6:30 p.m. along a flat, dry stretch in the 23100 block of the highway.

The cause of the collision remains under investigation.

At the hospital, the woman cooperated with troopers, submitting to a breath test that showed no indication she had been drinking alcohol. She did admit to having smoked marijuana, and the trooper reported evidence that she appeared to be under the influence.

They obtained a search warrant to draw blood for testing.

“Right now, we will be sending the blood to the toxicologist to get the blood reports back,” trooper Keith Leary said.

Lee told a trooper her children, 5 and 1, were fighting and screaming in the back of her eastbound Durango just before the crash, and she turned her head to check on them.

In front of her, an eastbound Chevrolet Blazer was stopped to make a left turn. There also was a white minivan stopped behind it.

The Durango swerved and clipped the white minivan. It then struck a maroon minivan head-on. Another vehicle swerved to avoid the wreck and ended up in a ditch, Leary said.

Twelve people — ages 1 to 72 — were involved. All wore seat belts or were fastened into car seats.

Those precautions might have saved lives, Leary said.

“We are hoping for the recovery of all of these people,” he said.

Lee received medical treatment at Providence before being booked into the Snohomish County Jail.

Her court-appointed attorney on Tuesday argued that there was no evidence Lee was affected by marijuana when the crash occurred. He also questioned whether turning around to check on her children was a reckless act under the law.

Everett District Court Judge Tam Bui said a combination of factors — the pipe in the car, the alleged acknowledgement that she had smoked marijuana earlier that day and the turning around to look at her children — established probable cause for Lee’s arrest.

Eric Stevick: 425-339-3446, stevick@heraldnet.com