NEWARK - A New York City doctor has been charged with groping a teen girl on a Newark-bound United Airlines flight last month, according to federal court documents.

The girl's family has also filed a complaint against United Airlines for the way the incident was handled after the teen reported the groping to a flight attendant, but allowed the man to leave the airport after the flight landed, according to a report in the Washington Post.

Vijakumar Krishnappa, 28, of New York City, was charged July 24 in federal court in Newark, a day after the flight that originated in Seattle, according to court records filed by the FBI charging him with criminal sexual contact.

Krishnappa was sitting next to the girl, who was traveling alone, authorities said. The girl fell asleep and awoke to find Krishnappa's hand on her thigh, authorities said. He quickly removed his hand, the girl told authorities.

After the teen fell asleep again, Krishnappa groped her a second time and tried to put his hands in her pants, but she was startled awake, authorities said. She flagged down a flight attendant to report the incident and was moved to another seat, authorities said.

But when the flight landed, Krishnappa was not detained, the attorney for the 16-year-old's parents told the Washington Post. Krishnappa as a doctor in the United States on a months-long fellowship, the report said.

Authorities tracked Krishnappa by using a flight manifest and showing the girl a photo lineup, the report said.

An attorney for Krishnappa told the Washington Post that his client denies the charges.

A spokesman from the Federal Aviation Administration told the Washington Post airlines typically notify law enforcement about incidents before landing.

"The safety and security of our customers is our top priority. We take these allegations seriously and continue to work closely with the proper authorities as part of their review," a spokesperson for United Airlines said in a statement.

Cindy Capitani may be reached at ccapitani@njadvancemedia.com. Follow her on Twitter @cindycap. Find NJ.com on Facebook.