The police watchdog is to reinvestigate the Metropolitan Police over their handling of the inquiry into the murders of four young men by serial killer Stephen Port.
The Independent Office for Police Conduct (IOPC) said it would look into how Scotland Yard investigated the cases during Port's killing spree in Barking, east London, from June 2014 to September 2015, after none of the 17 officers involved in the case faced disciplinary action.
Solicitor Neil Hudgell, speaking on behalf of the victims' families, said this was "the only logical decision open to the IOPC following the weight of evidence heard at the inquests".
The Metropolitan Police said it would offer "every support" to the fresh investigation.
Jurors at the inquests into the deaths of Anthony Walgate, 23, Gabriel Kovari, 22, Daniel Whitworth, 21, and 25-year-old Jack Taylor concluded that police failings "probably" contributed to the deaths of the three last victims, all of whom were unlawfully killed.
The jury's findings, in December last year, prompted the IOPC to announce that it would consider reinvestigating.
Officers denied accusations of prejudice and homophobia
Graham Beesley, the IOPC regional director, said on Thursday: "Since the inquests concluded, an IOPC team has been closely examining the original investigation material and comparing it with the information and verbal accounts provided to the new inquests.
"A matter can only be reinvestigated by the IOPC if we are satisfied that the original investigation was materially flawed in a manner which had an impact on the subsequent decisions made on discipline, performance and/or referral to the Crown Prosecution Service, and/or there is 'significant new information' that requires further investigation.
"In this case, the reinvestigation process has identified evidence which meets both the significant new information and material flaw categories, and we believe a proportionate - but thorough - new investigation is in the public interest."
He said the decision to reinvestigate "does not necessarily mean that the entirety of the original investigation will be examined again".
The inquest jury found that officers in Barking missed repeated opportunities to catch Port after he plied his first victim, Mr Walgate, with a fatal dose of the date-rape drug GHB and dumped his body.
Port struck three more times before he was finally caught, killing each victim in near-identical circumstances, with police failing to link him to the deaths despite detective work carried out by the victims' family and friends that would lead them to the culprit.
Officers had denied accusations of prejudice and homophobia, instead blaming mistakes on being understaffed and lacking resources, with some acting up in senior positions.
Port, 46, a bus depot chef, will die in prison after being handed a whole life sentence at the Old Bailey for the murders and a string of sex assaults.