The mother and father nearly cried when they watched the videos. Sitting in the St. Mary’s County prosecutor’s office this month, the parents of a 16-year-old autistic boy finally watched the notorious cellphone recordings that documented the alleged abuse of their son by two teenage girls.

One clip showed the Chopticon High School sophomore, whose middle name is Michael, being coerced onto a frozen pond and crashing through while the girls sat on a guardrail, giggling and filming. A second clip showed the older girl holding a knife to the boy’s throat, chastising him for not following orders to not mention their friendship to others. Another showed the girls — fellow students whom he considered his friends — trying to run him over in a car.

“I was holding back tears, but we powered through it,” said the father, a federal government contracting analyst whose descriptions of the footage are the first beyond what authorities released three months ago. “It was just very disturbing to see your loved one tormented that way. We wanted to see them so we could understand the gravity of the situation.”

On Thursday, one of the girls, Lauren A. Bush, 17, will appear in Circuit Court, where her attorney will ask a judge to dismiss the most serious charge, first-degree assault, and transfer her case to juvenile court, where she would face a maximum of four years behind bars. If convicted in adult court, the Chopticon junior could face 80 years.

In court papers, her attorney, Brian Thompson, argues that prosecutors do not have enough evidence to support first-degree assault, a charge that instantly put Bush’s case in adult court. Bush, who voluntarily committed herself to a secure juvenile detention center in Montgomery County, was trying to “frighten” Michael, not seriously injure him, according to her attorney’s motion.

“This is not about whether we like what she did or what we saw on these videos,” Thompson said in an interview. “We as a society have a choice when it comes to our kids. Do we try to help them . . . or warehouse them? Lauren’s a 17-year-old who’s never been in trouble before. She’s not going to get rehabilitated in an adult system — everyone knows that.”

But St. Mary’s prosecutor John Pleisse told a judge in April that authorities also have been investigating allegations that Bush and her friend bullied two other people — including a second disabled student at Chopticon. So far, no charges have been filed.

Michael’s parents said they want Bush punished as severely as possible. They weren’t sure they could bear to see the cellphone videos, which in March led to the arrests of Bush and her 15-year-old friend and triggered worldwide media coverage.

The 15-year-old, a Chopticon sophomore whom Michael considered his girlfriend, was prosecuted as a juvenile in April and sentenced to a maximum of six years in a state juvenile facility. (The Washington Post generally does not name juveniles charged with crimes.) In that trial, St. Mary’s County Judge Michael Stamm viewed the cellphone videos behind closed doors.

Pleisse showed the parents 10 video clips, Michael’s father said, but did not give the parents copies of the footage.

One clip, the father said, showed the girls trying to run Michael down after dropping him off in front of his home. “Whoever was driving started aiming the vehicle toward him, gunning it like they were going to run him down,” the father said. “He was trying to evade them, but he wasn’t very vocal. They were giggling.”

The father said he was most disturbed by a video showing Bush kicking Michael in the stomach and groin, pulling him by his hair and putting a knife to his throat. “That was my son being assaulted in my house with one of my kitchen knives. It was really disturbing they would do that — and film it,” he said.

Another clip showed the three teenagers at a park at night, with the two girls inside a car. The headlights shone on Michael, who was standing in front. “They were trying to get him to commit a crime — to expose himself,” the father said. “The younger girl said she’d give him $300 if he would show his private parts.”

Another video showed the girls trying to coerce the boy into fetching the family dog and have sex with it. “I don’t know where this would have ended if the girls hadn’t been arrested,” the father said.

Even though two months have passed since the two arrests, Michael rarely opens up to his parents about the incidents.

“I would like for him to see a medical doctor to examine him physically and psychologically,” the father said. “He was kicked around pretty hard, and he may have some internal injuries we may not know about yet.”

After watching the videos, Michael’s mother said she asked her son whether he wanted to hang out with the girls again — an idea he’d voiced before. “He just said, ‘I’m over them,’ ” the mother said.