THE reputed head of San Francisco's Wo Hop To triad was last week released by Hong Kong police after vital evidence needed from the US Government to complete extradition proceedings failed to arrive within the 60-day time limit. Peter Chong Ping-keung left the territory after being freed from the Lai Chi Kok Reception Centre last Tuesday. A Hong Kong lawyer, acting on behalf of the Federal Bureau of Investigation (FBI), withdrew the case after the time limit for the evidence to be produced expired. Chong is believed to have boarded a ferry to Macau the same night and has not returned to Hong Kong, where he could again face extradition proceedings based on any new evidence presented to Hong Kong officials. Macau has no extradition treaty with the US. Chong, 50, who lives on Tai Hang Road, was arrested on October 9 when he returned from a trip to Macau. He was first picked up in San Francisco in January, 1992 during a raid on an illegal gambling house. The arrests of Chong and 18 of his alleged accomplices in the US were seen as the culmination of a three-year FBI investigation into gangs on the US West Coast. Meanwhile, a suspected Sun Yee On office bearer, Keung Pui-wah, was released on bail after walking into a Tuen Mun police station with his legal team last week and surrendering. Known as Crazy Pui and reputed to be the gang's Tuen Mun regional commander, Keung gave himself up after learning that detectives wanted to question him in connection with a triad initiation ceremony four years ago. Keung walked into the police station unannounced last Wednesday morning.