The police watchdog will reassess the force’s inquiries into the deaths of Anthony Walgate, Gabriel Kovari, Daniel Whitworth and Jack Taylor, who were killed by Port in 2014 and 2015.
Jurors concluded police failings “probably” contributed to the deaths of Port’s second, third and fourth victim, after officers failed to link the men’s deaths.
Following the inquest’s conclusion, the Independent Office for Police Conduct (IOPC) said it was deciding whether to re-examine the original inquiry.
And now the IOPC has confirmed it will reinvestigate the Metropolitan Police Service (MPS), after the 2021 inquests “revealed previously unknown evidence”.
The Met voluntarily referred the case to the IOPC in October 2015, and the initial investigation was completed in August 2018.
The IOPC’s original investigation examined the actions of 17 officers, all but one of whom gave no comment interviews, and chose to provide written responses to the investigators.
An IOPC spokesperson said: “During the inquests new evidence, previously unknown to us, was presented by officers who had been subject to the IOPC investigation, by other officers who gave verbal evidence and in documentary form by the MPS.”
While IOPC regional director Graham Beesley said: “Since the inquests concluded, we have been closely examining the original investigation material and comparing it to the information and verbal accounts provided to the new inquests. This has been a complex task.
“This has been necessary to ensure the reinvestigation decision process was in line with legislation.”
Rules around the IOPC choosing to reopen an investigation stipulate that the watchdog must be satisfied that the original investigation was “materially flawed” and had an impact on decisions around “discipline, performance and/or referral to the Crown Prosecution Service.”
It may also reinvestigate if there is “significant new information” which requires it, which must offer a “real possibility” it could have led to different decisions on the investigation outcome.
Any investigation must also be in the public interest.
Mr Beesley said: “In this case, the reinvestigation process has identified evidence which meets both the significant new information and material flaw categories.
“We believe a proportionate - but thorough - new investigation is in the public interest.”
He added: “The original investigation needed to be wider in scope and, therefore, certain lines of enquiries were not followed.
“Had this information been known at the time it may have led to different decisions on outcomes.
“A new team has been appointed and they will decide the scale and scope of the new investigation.
“The reinvestigation decision does not necessarily mean that the entirety of the original investigation will be examined again.
“It would not be appropriate to comment further on any future lines of enquiry at this stage.
“We recognise this process has taken some time to complete and I would like to thank everyone for their patience.
“Those who have been closely impacted, including the families of the young men, and the officers who were originally investigated were consulted and have been regularly updated.”
Acting deputy Met commissioner Helen Ball said the force would give every support to the IOPC during its reinvestigation.
“The deaths of these four young men is a tragedy and we are deeply sorry there were failings in our police response,” she said.
“Again, I give my own and the Met’s heartfelt apologies.”
Ms Ball added: “The whole of the Met is committed to improving our investigations, our relationships and the trust people have in us to keep them safe.
“Since the deaths of Anthony, Gabriel, Daniel and Jack we have worked hard to ensure the service we provide is better while understanding we have more to do.
“If the IOPC reinvestigation makes further recommendations for improvements we will of course consider those very seriously, in addition to any misconduct matters that may arise.”
She confirmed that the officers involved had been informed of the decision to reinvestigate.
A spokesperson for Sadiq Khan, the mayor of London, saidthe mayor welcomed the decision.
He said: “The quality of the investigation carried out by the Met at the time of the murders raised a number of serious concerns – particularly around homophobia - and it is right that they are being looked into again in more detail.
“We owe it to the victims, their loved ones and all those impacted to ensure nothing like this can ever happen again.
“The mayor is fully committed to holding the Met to account and working with them to ensure all learning from the deaths of these innocent young men is translated into meaningful action and change.
“It is vital that London’s LGBTQ+ community has confidence in our police and the Met are able to gain the trust and confidence of all the communities it serves so that every Londoner, regardless of background or postcode can feel safe, protected and served.”