He said the North Korean leadership was displeased with their reports.
Mr Evans said Mr Wingfield-Hayes was singled out over some of his reports for TV and online.
Totalitarian: North Korean leader Kim Jong un
Reuters
Speaking live to Radio 4's Today programme he said: "They were, as I understand, at the airport waiting to get on a flight.
Mr Wingfield-Hayes was questioned for eight hours
BBC
"Just as they were about to board the flight, Rupert was held back.
"He was then taken to a hotel, a separate hotel to where we were and interrogated for eight hours."
North Korea is said to have tested ballistic missiles recently from these launchers
EPA
An interrogator told Mr Wingfield-Hayes he had been the official to prosecute Kenneth Bae - a Korean-American missionary who was sentenced to 15 years' hard labour in the country.
Mr Evans said that Mr Wingfield-Hayes was told to sign a confession confirming that his work had been inaccurate and the authorities were particularly concerned about two incidents.
In one, Mr Wingfield-Hayes had questioned whether a visit by VIPs to a hospital had been staged by the authorities to make it seem better than it was, and another one when a cameraman was asked to delete pictures.
He said he believed his three colleagues were currently at the airport waiting to leave.
