HANOI —18-year-old actress Hoang Thuy Linh has been caught having sex on video and is facing great criticism for it in her country of Vietnam.In Vang Anh’s Diaries, Thuy Linh portrayed a sweet, innocent high school girl, modern and stylish but determined to uphold the traditional virtues of “cong, dung, ngon” and “hanh,” which promote women as charming, soft-spoken, and chaste.

Then the 16-minute video hit the Internet last month featuring Thuy Linh in bed with her former boyfriend.

On Thursday, Hanoi police detained four college students accused of posting the sex clip to the Internet. They could face charges of “spreading depraved cultural items,” which carries a sentence of six months – 15 years, if convicted.

Police identified the man in the clip as 20-year-old Vu Hoang Viet, who is currently studying overseas. They said a friend copied the film off of Viet’s laptop, and passed it along to other friends who then posted it online.

Most of the public’s ire has been directed at Thuy Linh rather than Viet and the video has been the talk of the nation.

The scandal also has disillusioned many of Thuy Linh’s biggest fans.

“She was supposed to set a good example for Vietnamese students nationwide,” said Chi, 14, a Hanoi junior high school student who declined to give her full name to The New York Times. “Now this scandal has ruined everything. It’s completely destroyed her image.”

Unlike the stars of the American sex vids — Paris Hilton, Kim Kardashian, Chyna, and the like, Thuy Linh is not being seen in anything like a favorable light by her fellow country people.

“People will forgive him, but not her,” said Tran Minh Nguyet of the Vietnam Women’s Union, which promotes gender equality in the nation. “Vietnamese think it’s OK for a boy to have sex at that age, but not for a girl. It’s absolutely unfair.”