A woman accused of killing four people, including a 6-year-old boy, while running her car into pedestrians outside a California church appeared in court Friday cuffed to a gurney and pleaded not guilty to vehicular manslaughter charges.

An attorney for Margo Bronstein, 56, entered the plea on her behalf to four counts of gross vehicular manslaughter and one count of driving under the influence of a drug causing injury.

Bronstein was wheeled into court on the gurney by two attendants from an ambulance company. She was propped up with pillows and spoke only to her lawyer.

A judge ordered her held on $500,000 bail, the amount requested by prosecutors.

Bronstein's attorney Jeffrey Gray told the judge the collision appeared to be an accident, not intentional.

Outside court, Gray urged people not to jump to conclusions, noting the result of toxicology tests were not yet available and the cause of the incident was still unclear.

He said possibilities such as a malfunction of her specially equipped car, which has hand-controlled brakes, or an adverse reaction to her prescribed medication had not been ruled out.

"My concern is there tends to be a lot of, almost a mob mentality about this case," Gray said. "It's a tragedy. It's not fair to Miss Bronstein, it's not fair to the decedents' families to speculate as to happened."

He would not discuss any medication she might have taken. But the lawyer did say Bronstein "does not live her life recklessly."

He said she was brought to court on the gurney because she had been injured in the accident and because of disabilities she has had since birth.

Five children and eight adults, including the suspect and the driver of another car, suffered injuries such as broken bones, abrasions and head trauma in the crash Wednesday after a student Christmas concert at St. James Catholic Church in Redondo Beach, police said.

Samuel Gaza, 6, died late Thursday at a hospital.

Three adults died earlier, including the boy's mother, Martha Gaza, 36; along with Mary Anne Wilson, 81; and Saeko Matsumura, 87, all of Torrance.

Officials said they do not have information linking Bronstein to any prior arrests or DUI-related incidents.

She had a perfect driving record but was restricted to driving a vehicle with hand brakes, an additional right-side mirror and adequate signaling device, according to Department of Motor Vehicle records.

Friends and neighbors said she used crutches at times and a motorized wheelchair for longer distances, but they did not know why.

They said she is friendly and deferential.

"She's very personable, very kind," Vanecia Wiley, a manager at the senior housing community where Bronstein lives, told the Los Angeles Times. "She doesn't want to be in anyone's way."

Gray's attorney said she was not doing well in jail, where she was "a fish out of water."

"Two days ago, three days ago, people that knew her couldn't believe that she'd be in this situation," Gray said.