Serial killer Stephen Port had a 'voracious appetite' for meeting 'very young' men and spent time with 'vulnerable' boys to such an extent that his neighbour considered he might have 'paedophile tendencies', a court heard.
The 46-year-old was given a whole-life term in 2016 after he murdered four men by using lethal doses of the date-rape drug GHB.
Anthony Walgate, 23, Gabriel Kovari, 22, Daniel Whitworth, 21, and Jack Taylor, 25, were all found dead near Port's flat during a 16-month period between June 2014 and September 2015.
Today, neighbour Ryan Edwards said while he had concerns about Port he was reassured by the killer that his interest in young men was legal and that the drugs he was using were for personal use only.
He also described how Port, who also sexually assaulted several men, had a 'strange' obsession with children's toys and tried to cover his murderous tracks by telling him his second victim Gabriel Kovari died in mysterious circumstances abroad.
Inquests into the four deaths in Barking, east London, which are being held yards from where Port lived and dumped his victims' bodies, are examining whether police actions could have stopped the 6ft 5in serial killer earlier.
Serial killer Stephen Port, 46, who was given a whole-life term in 2016 for the murder of four men, had a 'voracious appetite' for meeting 'very young' men, a court has heard
Mr Edwards told inquest jurors he struck up a friendship with Port due to them being neighbours and members of Barking's LGBT community.
He said their friendship was strictly platonic, and that Port would frequently invite him over to meet his new partner, something which occasionally gave Mr Edwards cause for concern.
He told the inquest jury: 'My slight concern with Stephen Port was sometimes the guys he would introduce me to were very young - 16, 17 sometimes, very close to the age of consent.
'Often there were difficult circumstances, broken homes, needing somewhere to stay, vulnerable.
'I was wondering if he was bordering on paedophile tendencies, but I didn't have any evidence.'
Mr Edwards added: 'He had a voracious appetite for meeting guys and I was always astonished at how he was able to meet so many, he wasn't exactly ''Mr Personality''.
'That was slightly strange.'
Mr Edwards also described being invited to Port's flat one evening to meet his 'new guy', only to find the male seemingly unable to speak and drugs paraphernalia on the coffee table.
Gabriel Kovari, 22, (left) and Anthony Walgate, 23, (right) were found dead near Stephen Port's flat
Two of Port's four victims were Jack Taylor (left), 25, and Daniel Whitworth (right), 21
Timeline of Stephen Port's crimes
June 4, 2014: Police find Stephen Port at Barking station in East London with a young man he had drugged who has collapsed. Port admits they had taken illegal drugs but is not arrested.
June 19: Anthony Walgate, 23, given drug overdose and raped by Port who dumps body outside his flat and calls 999, claiming he has found an unconscious man.
June 26: Port suspected of lying to police and charged with perverting the course of justice. Released on bail. He is not accused of murdering Mr Walgate.
August 28: Gabriel Kovari, 22, given an overdose and raped by Port who dumps the body against a graveyard wall.
September 20: Daniel Whitworth, 21, given a drug overdose and raped. Port dumps his body against the same graveyard wall. Mr Whitworth is wearing Mr Kovari's top and is in a bed-sheet which has Port's DNA on it.
October 1: Detective Chief Inspector Tony Kirk tells local paper the three deaths within a mile of each other are not being treated as suspicious.
March 23, 2015: Port jailed for perverting the course of justice by lying over Mr Walgate's death. Released on licence in June with an electronic tag.
June 2015: Inquests into the deaths of Mr Kovari and Mr Whitworth were held, which were later set aside at the High Court in the wake of the murder trial.
September 13: Jack Taylor, 25, given a drug overdose and raped by Port. Body found next to the same graveyard.
October 15: Port arrested on suspicion of four murders and charged. Later charged with attacks on eight other men.
November 23, 2016: Port is convicted of 22 offences against 11 men, including four murders, four rapes, four assaults by penetration and 10 of administering a substance. He was cleared on three counts of rape.
November 25: Port is handed a whole-life sentence for the four murders.
He said: 'I did ask Stephen about it and he reassured me it was for his own personal use and reassured me not to worry.
'Rightly or wrongly, drugs are very prevalent on the gay scene, I don't see it as my place to police that.'
Mr Edwards said he would have reported concerns about Port's young companions and about drug use if there was any evidence of criminal activity, as he had done with a previous friend.
He also described how Port loved playing with Transformers toys, specifically the ones designed for children.
'(It was) strange for a grown man,' Mr Edwards said, 'but I took Stephen for his quirks, and there were many.'
The court also heard how Port tried to cover his murderous tracks by telling his neighbour his second victim Gabriel Kovari died in mysterious circumstances abroad.
Mr Edwards first met Mr Kovari after Port - who was said to have 'a revolving door of boys coming and going' - invited him round to meet his 'new Slovakian twink flat mate' (Mr Kovari) on August 24 2014.
The following day, Mr Kovari said to Mr Edwards that Port 'is not the person you think he is, he's not a nice man', prompting Mr Edwards to offer him shelter at his home nearby.
But Mr Kovari did not reply to Mr Edwards's follow-up messages.
He was found dead on August 28 in a secluded corner of St Margaret's Churchyard, near Port's flat in Barking, east London, unbeknownst to Mr Edwards.
Two days earlier, Mr Edwards was contacted by Port saying Mr Kovari had moved out.
Port followed this by asking Mr Edwards if he had seen Mr Kovari around, floating the idea that he moved to Spain, before texting him on September 11 to say the young man had in fact died on a flight abroad.
In one text, shown to inquest jurors on Thursday, Port wrote: 'Hey neighbour, have just heard sum (sic) sad news from one of Gabriel's friends that Gab did return to Spain to be with his bf (boyfriend) and he died on arrival from an infection.
'His (sic) being buried in slovkya (sic). Please don't put on FB (Facebook) or mention to anyone else as his family are in bits.'
Mr Edwards said he found Port's story to be suspicious, but did not have any reason to disbelieve him.
In fact, Mr Edwards was unaware that Mr Kovari had died on August 28 in Barking until over a year later because he was away that month.
Anthony Walgate, 23, Gabriel Kovari, 22, Daniel Whitworth, 21, and Jack Taylor, 25, were all found dead near Port's flat between June 2014 and September 2015.
The inquests continues.