SALEM — A mother and her young twins were wrapping up their Sunday evening at Salem’s Halloween celebration when the 10-year-old girls realized they’d forgotten something. Just steps from downtown, the family turned around to retrieve a stuffed animal.

The woman told police she looked both ways, then stepped into the crosswalk connecting the busy city center to the MBTA station, officials said. Then, a Subaru station wagon driven by Dexter M. Mitchell allegedly plowed into the family, throwing one girl over the hood and leaving all three seriously hurt.

The details, laid out in a police report filed in Salem District Court, emerged Monday as Mitchell was arraigned for allegedly driving drunk when he hit the group around 8 p.m. He is ­also accused of leaving the scene, though police said he returned after ditching a box of beer cans.

Mitchell, 52, of Beverly, was ordered held on $2,500 bail, which he later posted.

The police report said a witness told investigators she was driving behind Mitchell’s vehicle when she saw the crash at the busy intersection of Bridge and Washington streets. She reported that he was going about 30 miles per hour, which police said is the speed limit in that area.

Police arrived to find the mother “walking back and forth between the two girls with blood on her head and face, trying to comfort the girls.’’ All are expected to survive, police said, though one girl had a possible broken leg, along with head and back injuries.

Salem Police Captain Conrad Prosniewski said police are trying to determine the status of the intersection’s traffic signal at the time of the crash. He said investigators have witness accounts that said the “walk’’ sign was not activated, but have not confirmed that.

He said police are reviewing surveillance video and have not yet determined whether Mitchell had a green light.

In court, defense attorney Scott Masse said Mitchell is an educator who works with special needs students and has a 13-year-old child. He has no criminal convictions, Masse said.

“Unfortunately, it was an accident that happened, but there’s no evidence that it was careless,’’ Masse said. “There’s no evidence that the vehicle was swerving. There’s no evidence like that.’’

Masse said Mitchell did not flee, but parked and walked to the scene.

Assistant Essex District Attorney Megan MacKenzie acknowledged in court that Mitchell returned, but added, “He does that only after taking the alcohol out of his car and throwing it in the dumpster.’’

The police report said Mitchell had parked his car next to the dumpster, where investigators found a 12 pack of Budweiser — “some empty some full.’’ He failed field sobriety tests and refused a chemical test, the report said.

Mitchell’s license was suspended for six months after he refused the chemical test. According to the Registry of Motor Vehicles, he had not had a traffic incident since 2001, when he was found responsible for an accident in Salem.

In 1995, Mitchell was cited for failing to yield to a pedestrian in Salem, and he had previously had his license revoked for repeated violations dating back to the 1980s, according to RMV records.

As Mitchell appeared in court Monday morning, Salem was again filling up with visitors ready to celebrate Halloween. Assorted ghouls, jesters, and comic book characters strolled the historic downtown, but no signs remained of the real-life horror that had unfolded the night before.

A few blocks from the scene of the crash, Dan Shuman, owner and bicycle specialist at Salem Cycle, said downtown is generally very pedestrian friendly, but he encouraged anyone on the streets to be careful.

“Don’t think the drivers will be the responsible ones,’’ Shuman said. He added that the intersection where the crash happened is usually busy but safe. Given the holiday crowds, however, he said he hoped police would pay special attention to the crossing there.

Prosniewski, the police captain, said the Halloween season had otherwise been smooth around town.

“It’s an unfortunate and tragic event that none of us want to see happening,’’ he said of the crash.

Andy Rosen can be reached at andrew.rosen@globe.com. Follow him on Twitter at @andyrosen.