A police officer who investigated the death of Barking serial killer's fourth victim was "absolutely flabbergasted" to learn of similarities between the deaths of his other victims, an inquest has heard.

Port took the lives of Gabriel Kovari, Daniel Whitworth, Jack Taylor and Anthony Walgate between 2014 and 2015 by drugging them with fatal doses of GHB.

At an inquest, which is examining the competence and adequacy of the police investigation and whether Port could have been caught sooner, Insp Jason O’Donohue said he did not know the place where 25-year-old Mr Taylor's body was dumped was just seconds away from where Gabriel Kovari and Daniel Whitworth were found a year earlier - near Port's home in Cooke Street.

Mr O’Donohue was acting up as duty inspector in Barking, east London, in September 2015 when Mr Taylor’s lifeless body was discovered in a church graveyard by a park warden.

He was joined at the scene by two detectives – Yinka Adeyemo-Phillips and Peter Sweetman – who had been involved in the Kovari and Whitworth investigations, but neither told Mr O’Donohue that the deaths all involved young gay men with drug paraphernalia present, and with their mobile phones missing, he said.

Mr O’Donohue then declared the death unexplained but non-suspicious.

It was not until a month later that all four deaths became linked to Port. A police officer working on the investigation into Mr Walgate's death chanced upon a CCTV still of Mr Taylor walking alongside Port the night before he died.

Giving evidence to the inquests into Port’s four victims at Barking Town Hall, Mr O’Donohue said there had been no discussion between himself and the CID officers about the similarities between the deaths.

Henrietta Hill QC, counsel for the victims’ families, said: “If you had been made aware of more information of similarities between Jack Taylor and the other two, your decision-making might have been different?

Mr O’Donohue said: “It might have been.

“I wasn’t aware of any similarities other than all three deaths were involving men.”

He said he had no idea the bodies of Mr Kovari and Mr Whitworth had been found so close to Mr Taylor’s until Port went to court for murder.

“Not until I saw the court graphic for the trial,” he said.

“I was absolutely flabbergasted.”

Inquest jurors heard Mr Taylor’s family were upset about a lack of information from police on the investigation.

It was 10 days after they were first told of his death that Pc Jon Taylor, a parks officer who was first on scene, went to see his family.

It was during these discussions that they explained Mr Taylor was anti-drugs, and they believed the aspiring police officer had no reason to be in Barking.

The pc– who had no prior experience on investigatory work – then began contacting those who last saw Mr Taylor alive, leading him to look for CCTV in Barking train station which showed he met an unidentified tall man.

This was later identified as Port.

This comes after Mr Whitworth's partner Ricky Waumsley told the inquest he felt excluded by detectives - he feels because they were an unmarried gay couple.

Port, now 46, was handed a whole-life order in 2016.

The inquests continue.