Dejon L’Air Williams was speeding on Lee Highway on Tuesday night when her Honda Civic sideswiped another vehicle, careened into a median and then plowed into a minivan, Fairfax City police said.

The Civic burst into flames, police said, and bystanders scrambled to douse the fire and pull Williams’s two daughters from the wreckage, but the damage was done: Williams and 5-year-old Faith suffered deadly injuries, and 7-year-old Victoria was critically injured.

The driver of the Honda Odyssey minivan, Hamidullah Nabizada, 38, of Woodbridge, was badly hurt as well. With two dead and two clinging to life Wednesday evening, Fairfax police said the horrific crash was one of the worst they had seen in years.

“We’ve never had four people die in a crash in the 18 years I’ve been on the force — and that’s a possibility here,” said Sgt. Joe Johnson, a spokesman for the Fairfax City police.

Johnson said Williams’s speed caused the crash, but police did not release how fast her car was traveling. Johnson said nothing was found at the scene to indicate that Williams had been drinking or using drugs, but police are awaiting the results of toxicology tests.

Dejon L’air Williams of Cross Junction, Va., and daughter Faith, 5, died Tuesday night in a crash at Lee Highway and Jermantown Road. (FROM FAIRFAX CITY POLICE)

The crash occurred just before 11 p.m. near the intersection of Jermantown Road. Williams, of Cross Junction, Va., northwest of Winchester, was heading east on Lee Highway and attempted to pass another vehicle on the left when she sideswiped it, police said.

Williams’s Civic then struck the median and hit the Honda Odyssey as it was making a left-hand turn onto westbound Lee Highway from private property, police said.

Williams was pronounced dead at the scene, but her two daughters and Nabizada were rushed to the hospital, police said. Johnson said all of the occupants were wearing their seat belts.

It was the first fatal crash in Fairfax City this year, police said.

Over the past six years, Williams had been found guilty of speeding, reckless driving and following another vehicle too closely, court records in Loudoun County show.

Her family did not return calls for comment.