POLICE Narcotics Bureau officers yesterday arrested prominent trainer Eddie Lo Kwok-chow, 35, for alleged possession of dangerous drugs. A party of six officers, led by Detective Senior Inspector Ken Law Yue-kwong, raided Lo's Sha Tin Jockey Club staff quarters just after 3 pm. The horse trainer was then taken to the bureau in police headquarters, Wan Chai, where he was detained for questioning. Lo was later released on bail of $2,000 and was told to report to police next Saturday. Lo has three horses declared to run at Sha Tin this afternoon. Major-General Guy Watkins, the Royal Hong Kong Jockey Club's chief executive, confirmed last night they would run as usual. A police source said the action was prompted by the result of laboratory tests which confirmed substances seized from his home on Monday were cocaine and cannabis. Police visited Lo's apartment early on Monday and mounted a search of the premises. Top officials of the Jockey Club had been informed of the morning raid and were aware of yesterday's arrest. Lo has been a feature of local racing for the past 20 years. He was formerly a dual runner-up in the apprentices' championship in successive seasons 1974-75 and 75-76. He was made an assistant trainer in 1981 and an acting trainer in May 1986 when his boss, the legendary Derek Cheng Tai-chee was suspended pending investigations by the Independent Commission Against Corruption. Lo has held a full trainer's licence since December 1986, when he sensationally took over T. C. Cheng's stable after the latter's four-year disqualification. In recent seasons he has been known for his successful association with top American rider Declan Murphy. Their best season was in 1989-90 when Lo sent out 43 winners to finish third to Brian Kan Ping-chee in the standings. Last season his stable numbers were down and he managed 20 winners.