Liu Hao on TV Show 2010.11.

On the surface, Liu Hao seemed like an ideal candidate to become someone's romantic partner when he appeared on one of the many popular dating shows in China.

The 39-year-old music teacher wooed the show's audience, which sat entranced before a performance featuring his songbird voice, and won fans as he duked it out against a competing bachelor by energetically performing the running-man dance to techno music. Liu's wide grin reflected his confidence.

One woman was so enthralled that she picked him out of the eight eligible bachelors then appearing on the Happy League, a dating show in Northeast China's Heilongjiang province. Police now believe she picked a killer.

Authorities in Jilin, a city south of Heilongjiang province, said on Wednesday they detained Liu after they had received an anonymous tip more than a month ago from a viewer who had recognized the pudgy-faced contestant as a suspect in a murder case dating to the 1990s.

Although his formerly square jaw had since become rounded and his crewcut had been replaced with a more stylish buzz, his button nose and soft features had remained enough the same to give him away.

Police watched the tapes and found that Liu did indeed resemble Wu Gang, the suspect in a stabbing murder that occurred more than 13 years ago outside a restaurant in Jilin, said Li Ang, a police officer from the criminal investigation department of the Jilin Public Security Bureau.

Li said that after a monthlong investigation, Liu was detained.

"Liu had become accustomed to his new identity and fooling everyone around him - so he didn't think twice about going on the show," Li said. "He had managed to escape the law for so long that he became overconfident about not being caught."

Li declined to release further information about the case, saying the investigation is continuing.

An image of Li can no longer be found on the Happy League website, which has videos of other episodes.

Calls to the show's management office went unanswered on Wednesday.