A South Jersey woman has been charged with third-degree murder in the death of a Lower Merion firefighter who was on the scene of an earlier collision on I-76 when she struck him with her SUV, Montgomery County prosecutors said Tuesday.

Jacquelyn Walker, 63, of Egg Harbor Township, knew that her vehicle had faulty brakes and other mechanical problems but chose to drive anyway, authorities said. When she came upon the scene of an accident on I-76, they said, she veered off the roadway and struck a state trooper and three firefighters. Belmont Hills firefighter Thomas Royds, 49, went into cardiac arrest and later died at Paoli Hospital.

Walker was arraigned on the murder charge early Tuesday, along with counts of homicide by vehicle, aggravated assault with a vehicle, reckless endangerment and related offenses — charges that had been filed earlier. She was denied bail.

Her attorney, Gregory Nester, did not return a request for comment.

Walker was arrested at the scene of the July 24 crash on I-76 in Lower Merion that killed Royds and severely injured three others. .

Royds and his colleagues were stopped on the highway about 3:30 a.m. to assist in an unrelated crash involving two cars. While they were assessing the damage, Walker’s Jeep Grand Cherokee veered onto the shoulder where they were standing at a high rate of speed and hit them, according to the affidavit of probable cause for her arrest.

Other firefighters at the scene said Walker made no attempt to brake or veer away from the group, the affidavit said. And they said she ignored the flashing hazard lights of state police vehicles and fire trucks parked along the shoulder, warning motorists to avoid the area of the initial crash.

After the crash, investigators discovered that Walker’s vehicle showed “an extreme lack of maintenance,” according to the affidavit. The SUV’s brakes were barely working, they said, describing the left rear brake assembly as “catastrophically worn out” with barely any brake fluid. . The vehicle was operating with a spare tire , and a large pile of clothing had completely obscured the rear-view mirror, the affidavit said.

A mechanic who inspected the car after the crash said the brake pedal likely would have offered no resistance when pressed. Unlike Pennsylvania, New Jersey does not require annual safety inspections of non-commercial vehicles.

In an interview with detectives, Walker said she had gotten lost after visiting a mall in Quakertown hours earlier and believed she was driving on I-295 back to New Jersey at the time of the crash, according to the affidavit. Because she knew her brakes were not working, she said, she tried to pull off the highway to avoid the crash, and didn’t realize that state troopers and firefighters were on the shoulder of the roadway.

She told detectives she had been drinking a rum-and-soda cocktail as she drove around earlier that day, investigators said, but had poured the beverage out after the crash because “she knew it would look bad for her.” Toxicology tests found that Walker was not intoxicated at the time of the crash.

Detectives later discovered that Walker had been stopped three times within an hour earlier that morning by officers from different South Jersey police departments, the affidavit said. Each time she was stopped, it was because the lights on her vehicle were not working, the document said. And each time, the affidavit said, she told the officer who stopped her that she was looking for Route 38 but was “totally lost.”

All three officers issued her a warning, gave her directions and sent her on her way, according to the document. Two hours later, the affidavit said, she was in Lower Merion, where she struck Royds..