Serial killer Stephen Port's first victim's death was immediately "suspicious", a paramedic has told an inquest.
Fashion student Anthony Walgate, 23, was found outside Port's former flat in Cooke Street, Barking, his body upright and legs crossed.
Paramedic Antony Neil told jurors he regarded it as an "unexplained suspicious death" as, if Mr Walgate had had a seizure - as Port's 999 call had suggested - he would not have been propped up.
London Ambulance Service had received a call from Port at 4.05am on June 19 2014 and arrived in Cooke Street nine minutes later.
In the 999 call, which was played to the jury, Port denied seeing what happened to the collapsed man, saying he did not know if he was awake or breathing.
Port told the operator: "Looks like he's collapsed or had a seizure or something, just drunk.
"I was just driving in my car and just saw him lying on the floor, just got out, had a look at him."
"When I got to the body it was positioned cross-legged in an unnatural position from what the call was given as a possible seizure," Mr Neil said.
"My first impression was I could see the patient was deceased but if he had a seizure he would not be positioned as he was."
Mr Walgate had some blood around his mouth and had been "dead for quite some time", Mr Neil said.
Asked why he thought it was suspicious, he added: "The way it was positioned, it did not add up to the call I was given and because it was a young male, that's why it appeared suspicious to me.
"If someone had a seizure they would not be sat upright with their legs crossed. I have never seen that in my career."
Between June 2014 and September 2015, Port gave his four victims fatal doses of the date rape drug GHB at his flat in Barking, east London, then discarded them just metres away, an inquest has heard.
Police believe 6ft 5in Port wrapped his victims' bodies in bed sheets and carried them to the sites where they were found.
On Thursday, inquest jurors decamped from Barking Town Hall to view the crime scenes with coroner Sarah Munro QC, lawyers for police and bereaved families, and members of the press.
The 11 men and women were invited to examine each of the areas where the victims had been left and compare them with crime scene photographs of the bodies in situ.
Despite being convicted of lying to police about the circumstances of Mr Walgate's death, Port was not stopped until after he had killed three more men, the court has heard.
During their site visit, jurors walked to St Margaret's churchyard, some 300 metres from Cooke Street.
Gabriel Kovari, 22, and Daniel Whitworth, 21, were found dead by the same dog walker three weeks apart in 2014 beneath a large maple tree in a corner of the walled cemetery.
Mr Kovari's body was found at 9.01am on August 28 and Mr Whitworth was discovered at 11.20am on September 20, just a couple of metres away.
The final victim, aspiring police officer Jack Taylor, 25, was found by a parks worker on the other side of the stone wall at 1.10pm on September 14 2015.
Ms Munro said the worker flagged down two Metropolitan Police officers who observed "no obvious signs of life".
Mr Taylor was pronounced dead at 4pm by a forensic medical examiner, jurors were told.
During the 30-minute site visit, jurors walked past puzzled members of the public and a school where children could be heard in the playground.
After returning to the Town Hall the jury asked a series of questions.
On whether GHB was found on the bodies, Ms Munro said bottles were retrieved from all but Mr Kovari.
She said the exact route Port took to dispose of the bodies was unknown, but added they had walked one possible way.
The court had previously heard how Mr Whitworth was found holding a suicide note in his hand, which had been faked by Port in an effort to cover up Mr Kovari's death.
At the time, a friend of Mr Kovari had queried whether there was a link to the death of Mr Walgate - but that was dismissed by police.
Earlier inquests, later quashed by the High Court, reached open conclusions as a coroner could not rule out third party involvement in Mr Whitworth's case.
In 2016, Port, now 46, was found guilty at the Old Bailey of the four murders and sentenced to a whole life order.
The long-awaited inquest into the deaths is examining whether police made mistakes in their investigation which could have cost lives by failing to stop Port sooner.
The inquests are due to go on for up to 10 weeks.