The Metropolitan Police has confirmed detectives are investigating five people living in the UK – including one from Essex – over allegations relating to the Rwanda genocide 25 years ago.

The Home Secretary at the time, Jacqui Smith, had called for the man and three other men to be sent back to Rwanda after being accused of playing a role in the Rwandan genocide, but two judges agreed there was “a real risk they would suffer a flagrant denial of justice” if they were forced to return to Rwanda to face trial.

A spokeswoman for Scotland Yard said the force’s war crimes unit, which is part of the counter-terrorism command, received a referral from Rwandan authorities in January last year.

It related to five people in the UK and allegations of genocide offences in Rwanda dating from around 1994.

An estimated 800,000 Rwandans, mostly Tutsis but including some moderate Hutus, died in 100 days of slaughter and ethnic cleansing between April 7 and July 1994.

The spokeswoman said: “Relevant documentation to this was assessed by the war crimes unit and officers were also deployed to Rwanda as part of our initial work to scope the allegations.

“As a result, we have subsequently commenced an investigation which will initially involve a review of all the documentation transferred from Rwanda.

“Given the complexities involved, this is expected to be a protracted and lengthy process. Inquiries continue.”

All five deny the allegations against them and involvement in the genocide.

In July 2017, five men with the same names, all of Hutu ethnicity, had another extradition bid to have them returned to Rwanda blocked by the UK High Court.

At the time judges agreed there was still a risk they would be denied a fair trial if they were returned.