A Japan Airlines flight had to return to Hono­lulu after a male passenger sexually assaulted a female passenger in the airplane’s bathroom, the FBI said.

FBI agents arrested Michael Tano­uye, 29, of Hilo on Saturday night at Hono­lulu Airport for interfering with a flight crew and aggravated sexual assault aboard an aircraft. The sexual assault charge carries a maximum sentence of life in prison.

The flight was en route to Kansai International Airport when Tano­uye forced his way into a bathroom and sexually assaulted a woman, according to an FBI affidavit. The woman, who was returning home to Japan with her mother after a four-day vacation in Hawaii, went to use the restroom about an hour and 45 minutes after takeoff.

While struggling with Tano­uye, the woman was able to push the bathroom’s emergency button. The woman’s mother, the flight attendants and other passengers tried to open the lavatory door but were unable because Tano­uye was blocking the door, FBI Special Agent Necosie Wilson wrote in the affidavit. They had to open the door by removing screws from its hinges.

Flight attendants and passengers told the FBI that a male passenger was injured while struggling to subdue Tano­uye.

Before the incident, Tano­uye was heard shouting something incomprehensible, and his mother told a flight attendant he suffers from depression and is on medication. He stood up to walk around and appeared calm, telling flight attendants he was going to visit his grandmother. Flight attendants agreed not to serve him alcohol because he was on medication.

After the incident, Tano­uye’s mother gave him a dose of his medicine, and he fell asleep, the affidavit said.

The captain of the plane decided to turn around two hours after takeoff after hearing it took three passengers to keep Tano­uye calm.

Hawaii sheriff deputies took Tano­uye off the plane when it landed in Hono­lulu, and FBI agents arrested him, said Special Agent Tom Simon, spokes­man for the FBI in Hono­lulu. Tano­uye is being held without bail at the Hono­lulu Federal Detention Center.

He appeared in federal court for a brief hearing Tuesday, with what appeared to be an injury on the left side of his face. He replied "yes" when the judge asked whether he understood the charges. He wasn’t required to enter a plea.

Defense attorney Richard Sing declined to comment after the hearing. Tano­uye’s parents and sister attended the hearing and left the courthouse without commenting.

Assistant U.S. Attorney Larry Butrick told U.S. Magistrate Judge Kevin Chang there are additional charges and "mental health issues at play." Outside the courtroom, Butrick declined to elaborate on the pending charges, mental health issues or the facial injury.