A 35-year-old Indian man working in the United States was on Thursday convicted of sexually assaulting a sleeping woman aboard a Detroit-bound flight.

Prabhu Ramamoorthy, who lives in Rochester Hills, Michigan, faces up to life imprisonment following his conviction, The Detroit News reported. District Judge Terrence Berg will announce the sentence on December 12.

“We will not tolerate the behaviour of anyone who takes advantage of victims who are in a vulnerable position, and we are glad the jury agreed,” Attorney Matthew Schneider said. “We appreciate the victim in this case for her courage to speak out.”

Federal prosecutors said Ramamoorthy assaulted the 22-year-old woman during a Spirit Airlines flight from Las Vegas in January. The complainant said that when she woke up, she discovered Ramamoorthy sexually assaulting her.

Initially, Ramamoorthy claimed that he was in a “deep sleep” and had not committed sexual assault. But the accused later confessed to Federal Bureau of Investigation officials that he “might have” undone the woman’s bra and cupped her breast.