Curiosity landed a man into trouble when police caught him with a life vest he had taken from a previous flight at Beijing Capital International Airport, the China Times reported on Monday.

The 31-year-old man surnamed Yin is a designer at a railway design institute in Chengdu, southwest China's Sichuan Province. He took the life vest when he boarded an Air China flight from Chengdu to Beijing last Monday for a business trip. Police detained Yin on Saturday as he went through security checks at Beijing Capital International Airport before boarding a flight back to Chengdu.

"I took it out of curiosity. I thought it would be useful when I went swimming," Yin was quoted as saying by the newspaper.

Yin first told police that the life vest was a gift from a friend. He then admitted where he got the vest after being told it could not be found on the market, according to the report.

An airplane life vest costs about 300 yuan (US$36). But the vest Yin took has to be sent to its producer for re-examination before being put back on the plane. The re-examination fee is even higher than the cost of buying a new one, a police officer told the China Times.

According to the Law of Punishments in Public Order and Security Administration, the police decided to keep Yin in custody for seven days, the report said.