A deaf visitor from Japan was interrogated for seven hours at Honolulu International Airport, handcuffed and held overnight without ever having a sign language interpreter so she could understand what was happening, according to the American Civil Liberties Union of Hawaii.

The ACLU announced Thursday that it had filed a complaint with the U.S. Department of Homeland Security’s Office of Civil Rights and Civil Liberties, alleging discrimination by Customs and Border Protection agents and the Federal Bureau of Prisons.

“I was so scared and felt alone,” the woman said in a statement released by the ACLU. “For people with deafness, being cut off from our ways of communicating is terrifying. I have traveled a lot, but have never experienced anything like this at any airport ever.

“With this complaint I just want to make sure that other deaf people coming through Hawaii’s airports are treated with basic respect and dignity, and that disabilities are accommodated.” She asked not to be identified publicly for fear of retaliation by immigration officials.

The woman, who had previously studied in the United States, arrived in Honolulu at about 8:45 a.m. Jan. 31 to visit her boyfriend, who lives here. She was taken in for questioning about her school record, according to the complaint. But she couldn’t understand the questions she was asked.

Her written requests for an American Sign Language interpreter were rebuffed, according to Mateo Caballero, legal director for the ACLU of Hawaii, which filed the complaint April 24.

“We filed this complaint because there was a civil rights violation,” he said. “The law is clear — and it requires that federal agencies protect the civil rights of deaf individuals, including by ensuring effective communication during questioning by law enforcement. These federal agents ignored our client’s repeated requests for an ASL interpreter, denying her ability to communicate over seven hours of questioning and 16 hours of subsequent detention.”

The complaint calls for a thorough investigation and training of federal staff about communicating with deaf travelers to prevent similar problems in the future.

A spokesman for Customs and Border Protection said the agency is looking into the case.

“U.S. Customs and Border Protection has received the complaint and will address these accusations once our investigation is completed,” said Jaime Ruiz, chief of the Northern Border and Coastal Waters Branch of the agency’s Office of Public Affairs.

“CBP takes accusations of mistreatment against travelers with disabilities very seriously,” he added. “CBP officers receive extensive training in disability awareness and treat all travelers with disabilities with dignity, respect and professionalism.”

Repeated calls to the Federal Detention Center for comment were not answered Thursday.

The woman had applied to visit Honolulu through the Electronic System for Travel Authorization Visa Waiver Program. Her cellphone was taken from her shortly after questioning began, preventing her from contacting her family or boyfriend, who waited for her 12 hours at a cafe near the airport, according to the complaint.

After being interrogated for most of the day, she was taken to the Federal Detention Center and held overnight before being sent back to Japan the next day. She was not given an ASL interpreter or accessible telephone during her detention, according to the complaint. Her hands were cuffed behind her back during transfer to and within the detention center, cutting off her ability to communicate with her hands.

“Our client did not pose any threat or risk,” Caballero said.

He said the ACLU is focused on the civil rights issue and had no comment on why federal agents wanted to talk to her about her school record or what visa issues she might have faced.

U.S. law and agency regulations require the Department of Homeland Security to give individuals with disabilities equal access to services and benefits that are afforded other people.

“Our hope is that this will be an opportunity for public education not just for Customs and Border Protection, but any law enforcement or government official dealing with someone with a disability that might be deaf,” Caballero said. “They have to take that into consideration in their actions.”