A teenage girl was repeatedly groped by a 76-year-old man seated behind her on a plane traveling Friday night to Montana, according to FBI agents who arrested the septuagenarian on multiple felony charges.

Investigators allege that Vincent Kopacek sexually abused the 15-year-old victim on a July 8 Allegiant Air flight to Bozeman from Austin, Texas. Kopacek was released today from federal custody and ordered into home detention by a federal magistrate.

Pictured above, Kopacek has been charged with assault, abusive sexual contact, and attempted sexual abuse of a minor (who is identified by the initials “AG” in court filings).

As detailed in an FBI affidavit, Kopacek was seated directly behind the victim, who was in a window seat. The girl, who was traveling with her family on vacation, was seated next to her sister, while their mother was in an aisle seat. The girl’s father and brother were in a separate row.

According to Agent Matthew Deurmeier, prior to departing Austin, Kopacek “reached his hand around [the girl’s] seat, between her seat and the interior wall of the aircraft. AG did not know the male. AG described his hands as dry and rough.”

As the flight progressed, Kopacek “moved his fingers along AG’s seat then onto her body,” the affidavit states. Kopacek allegedly grabbed and squeezed the girl’s arm, “brushed his fingers along her torso,” and grabbed the child’s waist. “At some point,” Deurmaier added, Kopacek “touched her chest and groped her breast over her clothes.” The girl told investigators that Kopacek also tried to touch the front of her pants near her waistline.

During the flight, “AG” took over “twenty short videos and several photographs with her cell phone to document” the groping by Kopacek, who did not have another passenger seated next to him. 

The girl told police that she was “uncomfortable with the male touching her and during the flight she tried to distract herself so she would not cry.” The teen added that that she was scared the man would “get his hand into her pants” and that she “felt guilty for not speaking up” during the flight.

Upon arriving at the family’s hotel, “AG” told her parents about what occurred on the plane, prompting them to contact law enforcement.

Videos and photos from the girl’s phone “showed what appeared to be a larger, white hand in between AG’s seat and the interior wall of the aircraft,” Deurmeier wrote. “In an least one video, the hand is groping AG over her shirt while AG looks at her phone,” the agent added.

Kopacek, who lives in Fredericksburg, a central Texas city, was arrested Sunday when he checked in at the Bozeman airport for his flight home. If convicted of the most serious felony count, Kopacek faces a maximum of 15 years in prison and a $250,000 fine.