The serial killer Stephen Port had an “incessant” obsession with watching drug rape material and messaging men on hook-up sites, inquests into the deaths of four of his victims have been told. One laptop seized by police contained hundreds of thousands of lines of messaging about sex, pornography and drug-taking, said DI Mark Richards, the case officer on Operation Lilford, which was launched after the four deaths were eventually linked. Richards was giving evidence at the inquests of Anthony Walgate, 23; Gabriel Kovari, 22; Daniel Whitworth, 21 and Jack Taylor, 25, who were given fatal overdoses of the drug GHB by Port before being raped and their bodies dumped near his flat in Barking, east London, between June 2014 and September 2015. Port, now 46, is serving a whole-life order after being convicted of the murders at the Old Bailey in 2016. The inquest heard that Port was also found guilty of the drugging and sexual assault of seven living victims at his Old Bailey trial. Richards said that in addition, there were between five and seven other living victims identified by police who did not wish to take part in the prosecution. Asked if police could be certain Port had not murdered more people, Richards said: “We had to be 100% sure that he hadn’t killed anyone else”. He added that “extensive inquiries” had been made and police had reviewed 58 or 59 other deaths to see if there was any connection, but had found none. The long-awaited inquests, held at Barking town hall, will examine whether the series of police investigations into the men’s murders were adequate and whether lives could have been saved. Richards described Port’s pornography obsession as “absolutely incessant”. “It was all day, every day,” he told the jury. “There were hundreds of thousands of lines of messages.” Port would watch “a considerable and extensive amount” of drug rape material, viewing it for hours at a time on his laptop. He had a real obsession with drug rape pornography.” Port would pause messaging or watching the footage for about half an hour to go and meet men at Barking railway station and bring them back to his flat, then would continue viewing the material once the men were in his home. Port disposed of his phone handset or sim card after each of the deaths, Richards said. He would never reveal his address online when messaging men, but instead preferred to met them at Barking station then take them back to his nearby flat, Richards said. Police still did not know how he had dumped his victims’ bodies, but believed that Port, who was described as 6ft 5ins and of big build, had wrapped them in bed sheets and carried them to the nearby sites where they were found. The inquests, which are expected to last up to 10 weeks, continue.