A Devon man says he fears for the life of his friend who has been kidnapped in Saudi Arabia.
Mr Walkey and Paul Johnson worked together in Saudi Arabia
The captors of American citizen Paul Johnson say they will execute him by the weekend if militant prisoners are not released.
Tony Walkey from Totnes became friends with Paul Johnson when they worked together in Saudi Arabia.
Mr Walkey, who recently returned to Devon, has been following developments on the kidnap with growing concern.
He said: "He is a strong man with strong views and a great work ethic.
"He's very pro-Saudi. He wears Saudi dress into work twice a week and has Saudi friends.
"His colleagues at work are very shocked, as am I, at his current situation."
Paul Johnson was shown in a video posted on an extremist Islamic website on Tuesday night.
The 49-year-old defence worker has been missing for several days.
Also in the video was a man claiming to be the leader of Al Qaeda in Saudi Arabia.
He demanded that mujahideen be released from jails or Mr Johnson would be murdered.
Officials said the video was probably authentic.
Tony Walkey now fears for his friend.
"Whether or not the Saudi government is prepared to release the hostages, I think, is very debatable, but time is clearly of the essence and I'm very fearful for Paul's safety," he said.
The Saudi authorities have launched a search for Mr Johnson, 49, from New Jersey.
Adel al-Jubeir, the foreign affairs adviser to Crown Prince Abdullah, has said there will be no negotiation and it was not Saudi policy to exchange prisoners.