Two police officers who forged the signature of a double-murder suspect when he collapsed during questioning were jailed for 18 months yesterday. 'What they did was very foolish and unnecessary,' Judge Gareth Lugar-Mawson, told the District Court. 'It was not only foolish, but criminal.' Detective Sergeant Chong Kwok-wah and Detective Constable Wong Sek-wak had denied signing Lam Tin-ming's name on the confession after he had a massive heart attack on November 22 last year. 'The public deserves a full, thorough and scrupulously truthful inquiry into the death of any person who dies in police custody,' Judge Lugar-Mawson said. The judge called Lam, who died after the heart attack, a 'wretched, inadequate man'. But he said 'no matter how strong the circumstantial evidence was, there was always a doubt whether he was the man who murdered those two men'. Kevin Egan, for the defence, said the police officers' actions were 'stupid and unnecessary'. 'In order to tidy up the case they needed signatures, so they stupidly forged it,' he said. Two senior officers, Chief Superintendent Kerry Stanton Pearce and Chief Inspector Tsang Hin-ting, appeared as character witnesses yesterday. Mr Pearce had worked with Chong for nearly 17 years and considered him a friend. 'He has given the force and the community at large nearly 23 years of unblemished, loyal and dedicated service,' Mr Pearce said. But Judge Lugar-Mawson said the two officers' actions were 'all the more distressing' because they had the respect of their superiors. Crimes by police officers tear at 'the fabric of society', he said. Lam was suspected of the murders of Ho Chun-yau, 56, and Shum Ping-cheung, 64. Police found more than $200,000 in a flowerpot after a raid on Lam's home. Chong and Wong said the information about the money was given to them during the 'confession'.