The serial killer Stephen Port was identified as a “significant witness” and police knew of a previous male rape allegation against him within hours of the body of his first murder victim being found, an inquest has heard. Notes made by Ch Supt Andy Ewing, borough commander at Barking and Dagenham police, on the morning Anthony Walgate’s body was found, read “caller previous sex assault”, referencing an allegation found on the police national computer (PNC). Walgate, 23, a fashion student from Hull, was found dead propped up against a wall outside Port’s block of flats in Barking, east London, on 19 June 2014. He was the first of four young men murdered by Port, who fatally drugged his victims with the “date rape drug” GHB before raping them and dumping their bodies nearby. Inquests at Barking town hall into the deaths of Walgate, Gabriel Kovari, 22, Daniel Whitworth, 21, and Jack Taylor, 25, will examine whether police mistakes could have cost lives if Port could have been stopped sooner. Duty inspector Gary Learmonth, based at Barking and Dagenham emergency response, told the jury he arrived to take charge of the scene at 4.30am and recorded Walgate’s death as “potentially suspicious”. He alerted fellow officers to a “critical incident” on the police computer aided dispatch form. London ambulance service had been alerted to the body by an anonymous 999 call made by a male caller. Police checks swiftly identified that caller as Stephen Port, who lived at the flats, and Learmonth then identified Port as a “significant witness” who should be interviewed, the jury heard. When phone calls to Port’s number went to voicemail, officers repeatedly knocked on his flat door but received no response. An officer eventually managed to speak to Port, who had been inside the flat, and took a statement from him at 7.50am, the inquests heard. Learmonth remained at the scene for four and a half hours, but told the inquest he was not made aware that checks on the PNC had revealed an allegation of non-consensual anal rape against Port following an incident in 2012 in which he was accused of giving the victim poppers and alcohol. “That’s an important matter, isn’t it?” said Andrew O’Connor, counsel to the inquests. “Yes it is,” Learmonth replied. “If it is right that information was discovered that morning, that was a significant piece of information about the person who had called 999,” O’Connor said. Learmonth replied: “Yes, I agree.” The jury heard no further action was taken over the 2012 allegation as the complainant did not wish to support prosecution. O’Connor said the PNC report was printed off on 25 June 2014, one week after Walgate’s body was found. The inquest heard Port later told police he had met Walgate for a sexual relationship, and that he had picked him up by the arms and propped him up outside the flat. Crime scene manager Cheryl Kynaston said a special postmortem was held. Asked by Peter Skelton QC, for the Metropolitan police, whether she believed at that time that Walgate could have been murdered, she replied: “No, I didn’t. “I thought it was most likely he might have been moved after he died and that was strange, but nothing to suggest he had been murdered.” Port, now 46, was found guilty of all four murders and handed a whole-life sentence at the Old Bailey in 2016. The inquests, which will examine the “competence” and “adequacy” of the police investigation, are expected to last up to 10 weeks. The inquests were adjourned until Monday.