A gang of teenagers tried to extort $70,000 from another youth, a court heard yesterday. The defendants - including a 13-year-old girl - imprisoned Yeung Ting-fung, 16, and threatened to burn his house down if he escaped, the District Court was told. In January, Lau Tak-lok, 17, demanded $3,000 from Ting-fung. A month later, he was assaulted by Poon Wai, 17, for not paying, the court heard. On March 7, Ting-fung was held by the gang, which then demanded $70,000. Lau told him to get his parents to pay by saying he had had sex with a girl wanted compensation, the court heard. Lau took Ting-fung's wallet before letting him go to collect the money. The gang was arrested when the father called police. The other defendants are Ng Wing-ho, 14, Lo Pak-chi, 16 and Liu Wing-yi, 13. All deny false imprisonment. Poon also denies assault and blackmail. Ng denies blackmail. Lau admitted blackmail and theft. The trial continues before Judge Fergal Sweeney.