A New York City street filled with trick-or-treaters turned into a Halloween horror scene Saturday when a car jumped a curb and plowed into a group of revelers, killing three people and injuring four others including the driver.

The accident occurred at around 5 p.m. just as the group was walking down a quiet street in the Morris Park section of the Bronx.

A 52-year-old man behind the wheel of a black Dodge Charger plowed into the pedestrians on a sidewalk and then smashed through a fence in front of a home, police said. The car was left teetering on a brick wall. A child’s shoe and remnants of mangled stroller lay on the sidewalk, just feet away.

Witnesses described hearing a loud boom, followed by screaming and crying, then seeing a trail of mangled bodies in crumpled, bloodied costumes.

"I saw a torso on the sidewalk. I didn't know if it was a Halloween dummy or a real person," neighbor Fabio Cotza told the New York Post. "I just grabbed a whole bunch of towels and ran outside."

Moments before the car jumped the curb, the driver had crossed over a double yellow line in the road after bumping into the back of a Toyota Camry, police said.

"There was a family of kids trick-or-treating, walking behind me," Kristina DeJesus told WABC-TV. "All of a sudden ... I heard the boom, and the car like literally jumped over a parked car and flew into the gate, hitting a bunch of people."

The New York Post reports police believe the driver experienced a seizure or some other medical issue that caused him to lose control.

Louis Perez, 65, suffered severe head trauma and died at the scene, police said. His 10-year-old granddaughter and Kristian Leka, 24, were taken to a hospital where they later died. Police didn’t know how Leka was related to the others.

Authorities said a 3-year-old girl was critically injured. A 21-year-old woman, a 9-year-old girl and the driver of the car also were taken to the hospital with injuries not believed to be life-threatening.

"The little girl in the cat costume, she was hurt, she was screaming," Cotza told WNBC-TV. "It just didn't look real ... like this is a Halloween joke."

A crowd of costumed onlookers descended on the scene Saturday night as investigators worked to determine the cause of the crash. No charges have been filed.

Hours after the crash, neighbors gathered for a small candlelight vigil to remember the victims.

"This is a sad situation, especially today; it's Halloween," Anna Crecco said. "It's going to affect a lot, something like this has never happened here. Everyone's going to remember when they pass by."

The Associated Press contributed to this report.