An Oregon man seated next to a 13-year-old girl flying unattended on a flight from Dallas/Ft. Worth to Portland, Ore., last week, and repeatedly groped her and engaged in lewd acts, according to a complaint filed by FBI agents and Port of Portland officers.

Chad Cameron Camp, 26, of Gresham, Ore., entered a plea of not guilty to a charge of “abusive sexual contact,” Oregon Live reported. He has a detention hearing scheduled for Monday afternoon in U.S. District Court in Portland. He has no record of criminal convictions, according to Oregon Circuit Court records.

According to the complaint against Camp, a passenger aboard the flight notified the crew shortly after the plane took off that she saw him touch the girl inappropriately.

An attorney representing the child’s family, Brent Goodfellow, said Camp touched the girl 15 times before a flight attendant serving drinks saw his hand in the girl’s crotch and ordered him to move to another seat.

The flight attendant saw “a single tear coming down the victim’s cheek,” according to the complaint.

The girl’s father had paid American Airlines a $150 fee for “unaccompanied minor service,” which the airline says is to ensure that a child who is at least 5-years-old “is boarded onto the aircraft, introduced to the flight attendant, chaperoned during connections and released to the appropriate person at their destination."

Goodfellow said flight attendants seated the girl next to a window in a three-seat row when she boarded the plane. He said Camp boarded the plane wearing headphones and, according to the girl, was talking to himself before he sat in the seat next to her.

When the flight attendants offered Camp another seat, he replied, “No, I’m fine,” an FBI agent wrote in the criminal complaint.

“That’s a red flag,” Goodfellow told KOIN TV. “Anybody who’s been on an airplane ever is going to move out of the middle seat the second they can.”

According to the complaint, the girl said Camp brushed up against her upper arm and shoulder as he read a magazine, then stood up and leaned toward the window, his head about 12 inches from her face. When he sat back down, he touched the girl twice with his elbow, according to the complaint.

After offering to share his earphones so he and the girl could listen to music together, Camp repeatedly put his hand on the girl’s knee and upper thigh, according to the complaint. She moved his hand away and he allegedly put it back.

"She told this guy over and over, 'stop touching me,'" Goodfellow said. "At one point, he got angry and threw his earphones at her and continued to talk to himself."

Goodfellow said flight attendants moved the girl and the witness to the front of the plane and seated Camp near the rear. Upon landing, the girl was allowed to exit the plane while Camp remained in his seat.

"We take these matters very seriously and have cooperated fully and immediately with law enforcement officials in their investigation of the suspect," Ross Feinstein, an airline spokesman, wrote in an email to Oregon Live.

"Due to the pending criminal case against the suspect, we are referring all questions to law enforcement."

Goodfellow told KOIN that the girl didn’t use the bathroom after the flight attendant separated her from the suspect because she was worried about bumping into him again.

“She is already saying she doesn’t want to be on an airplane ever again,” Goodfellow told KOIN. “I sat with the family for about 3 hours… she didn’t want to be touched by her mom, every time she went to give her kind of a loving touch she would jump.”

Goodfellow said American needs to be held accountable and that the family is planning to file a civil suit against the airline.

“They didn’t make him move, they let him sit there until she was abused for 30 minutes,” he said. “From what I understand she was the only child on the airplane that evening, so it would have been pretty easy to take a few small steps.”

In May, an Oregon woman accused a female passenger of groping her on an Alaska Airlines flight from Las Vegas.