Detectives have appealed for people who may know an alleged serial killer accused of drugging and murdering four young men to come forward.
Stephen Port, 40, allegedly met his victims on gay websites and invited them to his house where he poisoned them with the party drug GHB.
After suffering from overdoses, the men, in their 20s, were dumped in or near a churchyard in east London.
Port, of Cooke Street, Barking, in east London, has been charged with four counts of murder and four counts of administering a poison with intent to endanger life or inflict grievous bodily harm.
He is due to stand trial in April next year.
Police said they want to speak to "anyone who has knowledge" of Port.
Detective Chief Inspector Tim Duffield, from the Homicide and Major Crime Command, said: "We are keen to speak to anyone who may have information in connection with these incidents, no matter how insignificant you may think it is.
"If you have any reservations about speaking to the police, please rest assured that your call will be dealt with in the strictest confidence.
"For anyone who feels anxious about talking directly to the police, I would urge them to speak to organisations such as Galop, a specialist charity that supports LGBT people affected by violence and abuse.
"They will be able to facilitate appropriate support and advice, maintain confidentiality and treat anything you tell them with the utmost sensitivity."
Detectives launched an investigation after four men died over a period of 14 months.
The first, Anthony Walgate, 23, was found dead on Cooke Street on June 19 last year. He was a fashion and design student at Middlesex University who was originally from Hull but living in Barnet.
The second victim, Gabriel Kovari, 22, was found by a dog walker near St Margaret's churchyard on August 28 last year. He was originally from Slovakia but lived in Lewisham, south London.
Just under a month later, on September 20 last year, the same dog walker discovered the body of Daniel Whitworth, 21, from Gravesend, Kent, near the same churchyard.
Then on September 14 this year, Jack Taylor, 25, a forklift truck driver from Dagenham, was found dead near the abbey ruins close to North Street.
The deaths were not initially linked but after further investigation they were referred to the Metropolitan Police homicide and major crime command on October 14.
The force has referred its handling of the case to the Independent Police Complaints Commission (IPCC).
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