A Massachusetts man was charged Wednesday with a felony after a 19-year-old woman accused him of sexually assaulting her while she was "half asleep" on a United Airlines flight from Tokyo to Virginia.

Georgiy Seryogin, 47, was arrested and charged with abusive sexual contact after the woman, who was seated next to him, told flight attendants and authorities that he had touched her leg underneath her clothes and rubbed his hand on her vagina, according to charging documents.

Seryogin was sitting in a window seat during the 13-hour direct flight in July 2018, and his alleged victim was sitting in the middle seat, according to an affidavit filed in the Eastern District of Virginia. They did not know one another prior to the flight.

The affidavit said the woman first woke up when she felt Seryogin reach across her to pet a cat that was traveling with a passenger in the aisle seat in their row.

"Based on my training and experience, individuals who commit sexual assaults aboard aircrafts often begin their sex crimes by slowly making physical contact with their victims in order to test them and observe their reactions, if any," FBI Special Agent Jeffrey Fuller, who specializes in aircraft crimes, wrote in the affidavit.

About 10 minutes later, the woman said she felt Seryogin rub her knee and inner thigh, and then he "put his hand against the victim's vagina, through her clothing and without her permission, and began to caress her vagina, while using his other hand to try to spread her legs apart," the affidavit said.

Seryogin had pushed up his armrest and partially covered the woman's leg with a blanket so that other passengers couldn't see what he was doing, the charging documents said.

The victim had her head turned away and down and was quietly crying as the assault happened, the affidavit said. She later said she was in "shock" and "froze" during the assault.

But she eventually pushed his hands off, and, after waiting a few minutes in "fear" and "feeling upset and confused," she got out of her seat and told flight attendants what had happened, the affidavit said. She was moved to another seat on the plane.

Fuller interviewed the victim shortly after she landed at Washington Dulles International Airport and said she told him the same statements that she told the flight attendants.

Her accusations were also consistent with a text she had sent her cousin, another message she had sent her friend and a note she had typed on her phone — when she thought she'd be too afraid to verbalize what had happened.

"This guy was touching me on the plane while i was asleep," she wrote to her cousin, before clarifying that she was "half asleep," the affidavit said. She added that she was wearing "torn jeans so he had ez access to my legs."

Seryogin admitted to investigators that he raised the armrest but said he did not remember touching the woman, the affidavit said. He said it was possible he was moving around in his sleep and accidentally touched her.

"The victim is confident, without any doubt, that (Seryogin) was awake when he sexually assaulted her, and distinctly remembers that she quickly looked at him when she pushed his hands off her inner thigh and vagina areas. At that point, the victim stated that Defendant (Seryogin) appeared to have a look of regret on his face, knowing what he did to her," the affidavit alleges.

Seryogin, a dual Russian American citizen, was arrested in Alexandria, Virginia, and released on bail Tuesday, according to court documents. His lawyer did not respond to a request for comment.

A United Airlines statement said that flight attendants reacted appropriately by moving the woman's seat and requesting that authorities meet the plane when it landed. The statement said the airline is cooperating with the criminal investigation and Seryogin has been banned from United Airlines flights.

"Sexual harassment, inappropriate behavior, intimidation or predation have absolutely no place anywhere in our society — including in our industry and on our aircraft," the statement said.

Last year, the FBI said that reports of sexual assaults on planes had increased by 66 percent between 2014 and 2017. The spike could be due to an increase in people reporting the assaults, but the actual number of victims is still likely underrepresented since sexual abuse victims are often reluctant to come forward.