An informer could be found guilty of trafficking in drugs and planting evidence on suspects even if he acted entirely on the instructions of police, a prosecutor said yesterday. William Lam told a High Court jury: 'Even if the bag of heroin had come from the police, the defendant would still be guilty because he was part of the crime.' The informer has denied trafficking in heroin and perverting the course of justice by planting drugs in a Mongkok hotel room. The prosecution alleges the informer misled the police by placing the drugs in a hotel toilet and then providing false information which led to six men being arrested. The informer claims he was blackmailed into helping police frame the men. Mr Lam said: 'If he took the drugs himself to put them there for the purposes of perverting the course of justice, he must be guilty of both charges.' But Deputy Judge Peter Longley asked: 'Are you suggesting they can find he was guilty of doing acts other than those alleged in the particulars of the offences?' The judge said the prosecution was bound by the details of the offences. The informer has alleged Inspector Ho Chi-kit and Sergeant Lo Wai-man gave him the drugs at Tsim Sha Tsui police station and threatened to frame him unless he planted them in the Mongkok hotel room. In his final speech to the jury, Mr Lam dismissed the defendant's claims as fanciful, ridiculous and incredible. He said the informer was making allegations against the police in order to get sympathy from the jury. 'If you believe him, he might get sympathy from you. But that is not a defence in law,' Mr Lam said. Defence barrister Chan Siu-ming said Inspector Ho would have had easy access to drugs because he was working for the Narcotics Bureau. Inspector Ho and Sergeant Lo had both since resigned from the police, he added. Mr Chan said the informer did not have a guilty mind because he had been working for the police at the time. The judge has requested the press not to publish the informer's name. The jury is expected to retire to consider verdicts today.