Hamid Nouri: How Sweden arrested a suspected Iranian war criminal

In the arrivals terminal of Stockholm Arlanda Airport, Swedish police were expecting someone significant.

On board a flight from Iran, they were told, was an alleged war criminal, an Iranian official named Hamid Nouri.

Unknown to him, police had been tipped off. Mr Nouri walked off the plane on 9 November 2019 and straight into custody.

A short time later, a Swedish official made a phone call to deliver a message: "You can go home now."

The recipient of the call had been at the airport, nervously waiting for confirmation of the arrest. He was one of several people whose actions had made the arrest possible.

In interviews with the BBC, they each explained their role in an extraordinary case, of significance in Iran and internationally.