Serial killer Stephen Port could be facing the rest of his life in prison when he is sentenced later for the murders of four young gay men.
The 41-year-old chef stalked his victims on dating websites and plied them with drinks spiked with fatal amounts of the drug GHB to rape them while they were unconscious.
He dumped their bodies in or near a graveyard within 500 metres of his flat in Barking, east London, and embarked on an elaborate cover-up.
He disposed of their mobile phones, repeatedly lied to police and planted a fake suicide note in the hand of one of his victims, taking the blame for the death of another.
Following an Old Bailey trial, Port was found guilty of the murders after a jury deliberated for 28 hours and 27 minutes. He was also convicted of a string of sex offences against seven other men who came forward following his arrest.
The deaths of Jack Taylor, Anthony Walgate, Gabriel Kovari and Daniel Whitworth over 15 months bore striking similarities but police allegedly failed to make the link until relatives of his final victim demanded answers.
The initial handling of the case provoked fierce criticism from friends, family and campaigners who had urged police to take their concerns seriously and act sooner.
Following Port's conviction, Commander Stuart Cundy said he had written a letter of condolence to the loved ones of the young men and apologised for "missed opportunities".
A total of 17 officers are being investigated over their handling of the case, seven of whom could face the sack if found to be guilty of gross misconduct.
Following the verdicts, Mr Taylor's family, who are planning to sue, said: "We do believe Jack would still be here if they had done their job.
"The police should be held accountable for Jack's death.
"We do understand it's not them who took Jack's life, but Stephen Port would have been stopped."
The family refused to accept Mr Taylor would have taken drugs willingly and put pressure on officers to treat his death as suspicious.
Human rights campaigner Peter Tatchell accused the police of "class, gender and sexuality bias" and said lives would have been saved if police had acted on concerns sooner.
The court heard Port had an insatiable desire for boyish-looking men he referred to as Twinks.
He trawled the internet for pornography involving inert young men being "raped" by older men.
The first victim, Mr Walgate, 23, was found dead in the communal hall of Port's flat in Cooke Street after he called 999 anonymously in the early hours of June 19 2014.
When police tracked him down, Port lied to officers to distance himself from the fashion student and occasional male escort.
He was later jailed for perverting the course of justice but continued to claim Mr Walgate died from taking his own drugs.
Second to die was 22-year-old Slovakian Mr Kovari, who was staying on Port's sofa as a temporary flatmate.
After killing him, Port spoke to his older sister Sharon on the phone and confessed he had a body in his bed.
But rather than going to police, he dragged the body to Barking Abbey graveyard to be discovered by a dog walker.
Port constructed a complex web of deceit, telling his neighbour that Mr Kovari died of an infection in Spain.
Over months, he posed on Facebook as an American student to probe Mr Kovari's grief-stricken Spanish boyfriend and divert suspicion by suggesting the victim had gone off to a sex party with "Dan".
Prosecutor Jonathan Rees QC told jurors that the misinformation was to "lay the groundwork" for implicating his third victim, Mr Whitworth, even though Port maintained his story.
Three weeks after Mr Kovari was found dead, the same dog walker stumbled across the body of Mr Whitworth, 21, from Gravesend, Kent, on September 20 2014.
In his hand was a suicide note taking the blame for Mr Kovari's death, saying: "We was having some fun at a mate's place and I got carried away and gave him another shot of G."
Police treated Mr Whitworth's death "at face value" and no efforts were made to verify the sham note which turned out to be in Port's handwriting, Mr Rees told jurors.
Mr Taylor, 25, died within hours of hooking up with Port on Grindr in the early hours of September 13 2015.
After killing him, Port got rid of the forklift truck driver's mobile phone and deleted their communication on the gay dating app.
Just after 1pm the next day, Mr Taylor's body was found by a refuse collector with a needle and syringe in his pocket.
Initially his death was treated as "non-suspicious", the court heard.
But CCTV footage from Barking Station emerged linking him to Port, whose DNA was found on a bottle of GHB also planted in Mr Taylor's trouser pocket.
Giving evidence, Port maintained his lying accounts and claimed he had left Mr Taylor "very much" alive after having "rampant" sex outside.
On why he lied to police, Port said: "The truth sounded like a lie, so I lied to make it sound like the truth."
But the prosecution rejected his explanations as absurd, ridiculous and cruel to the families who deserved to know the truth.
The jury convicted Port of a total of 22 offences against 11 men, including the four murders, four rapes, 10 counts of administering a substance, and four sex assaults.
He was cleared on three counts of rape.
Police have not ruled out the possibility there may be more victims of Port's sexual abuse and appealed for them to come forward.
Port will be sentenced at the Old Bailey by Mr Justice Openshaw later on Friday.