Hanoi police on Tuesday arrested a 39-year-old man suspected of raping a college student that he met online though a mobile chat app.
Doan Dinh Lan is a former member of the national karate team and a Southeast Asian Games silver medalist.
At the police station, Lan confessed that he befriended with the 19-year-old woman, identified only as B, on November 20, 2015.
Lan identified himself as a photographer and offered to take pictures for B.
When they met on the same day, Lan took B to a hotel in Cau Giay District and told the girl he would take take her photos at his studio there.
But when they entered a hotel room, Lan raped the student twice and filmed the alleged incident, according to the district police.
He also threatened to spread the videos on the Internet if B reported to the police.
Police said B told her family what happened and after being urged, she reported the crime the following day.
According to police, previously Lan was sentenced to 30 months' imprisonment for robbery.
Police are investigating the case.