A jury will look at whether "prejudice" played a part in how police initially treated the deaths of serial killer Stephen Port's victims, a coroner has ruled.
Port, now aged 44, drugged and raped four young gay men and dumped their bodies near his home in Barking, east London, between 2014 and 2015.
Following a trial at the Old Bailey, he was handed a whole life sentence for the murders of fashion student Anthony Walgate, 23, Gabriel Kovari, 22, Kent chef Daniel Whitworth, 21, and Jack Taylor, 25, a forklift truck driver from Dagenham.
A full inquest into all four deaths is expected to focus on possible failings by police after the victims' families questioned why Port was not stopped sooner.
Andrew O'Connor QC, counsel for the coroner, told a pre-inquest hearing at the Old Bailey that the provisional scope would cover whether prejudice of officers led to failings.
Mr O'Connor said that "the most important question" for the coroner to decide was whether police treating Mr Kovari's death as non-suspicious "was a failing and led to other deaths".
He told the court: "Everyone agrees one of the core issues is whether the police investigations into the four deaths were affected by prejudice of the sexuality of Mr Walgate, Mr Kovari, Mr Whitworth and Mr Taylor, and indeed Mr Port."
The lawyer said the inquest would not stop at examining individual officers if the evidence led to institutional prejudice.
Mr O'Connor said: "The investigation will not stop at establishing whether individual officers were biased, it will clearly need to go further than that."
He said the inquest would be making disclosure requests for any material relating to "these institutional issues".
During the hearing, Leslie Thomas QC, for victims' families, also called for the coroner to confirm she would call a jury for the full inquest.
He said: "Arguably there is a lot the police could and should have done.
"We say when you look at the test, you will be driven to the inevitable conclusion that a jury should be empanelled."
Judge Sarah Munro QC, sitting as assistant coroner for east London, said: "I have concluded that I do have a reason to suspect that the deaths resulted from the acts or omissions of police or police officers. There must be a jury inquest."
She set an eight-week inquest at the Old Bailey to start on the first Monday in January 2021.
Members of the victims' families, who had agreed to the date, had attended the two-hour hearing to confirm details ahead of the full inquest.
After the hearing, Andrew Petherbridge, the lawyer from Hudgell Solicitors acting for the victims' families, said: "The families were very pleased to hear the coroner say that she will sit with a jury. It is what they have always wanted.
"And while any delay to the inquest starting is frustrating for the families, they at least will have the legal team in place that they want and can now look forward with some certainty."
A further pre-inquest review will be held in February 2020.