The father of missing university chef Claudia Lawrence today took the search for his daughter worldwide with the release of a YouTube video appeal.
Peter Lawrence, 62, launched the four-and-a-half-minute "Claudia, Where Are You?" video to mark 100 days since Miss Lawrence, 35, disappeared in York.
She was last seen near her home on Heworth Road on March 18 and failed to arrive at work at the University of York's Goodricke College the following morning.
North Yorkshire Police have since classified their investigation as one of suspected murder and Crimestoppers has offered a £10,000 reward for information leading to the conviction of those responsible.
In his video, solicitor Mr Lawrence, from Slingsby, North Yorkshire, said he believed the internet was crucial to the search for his daughter.
"To get it on to the web gives a much greater breadth of exposure and the more it can be there in the forefront of people's minds, the better," he said.
Click below to watch the video
Mr Lawrence again urged people to come forward with information and not to protect anyone who may be responsible for his daughter's disappearance.
"There's someone out there, if you're that somebody you should jolly well be saying so," he said.
"There's no point in protecting anybody's relationships or lifestyle in the situation that we're in, it's just not fair to Claudia's family.
"For heaven's sake, please say something."
The video, produced by the York Press newspaper, includes clips from a BBC1 Crimewatch appeal showing reconstructions of separate sightings of a couple on Miss Lawrence's route to work on 19 March.
So far, the people seen that morning have not been identified.
"Somebody knows something about the sightings which the police have mentioned in press conferences and on Crimewatch.
"Even if that wasn't Claudia, somebody knows who it was, who the girl was, who the man was, on both occasions, and if they would just say so," Mr Lawrence said.
"It's not a time for protecting anybody, this is potentially a murder investigation."
Mr Lawrence said he had felt "numb" since his daughter disappeared and described how he frequently burst into tears when he thought about her.
He said: "It's just felt as though there's something missing and part of me missing really. I think I've previously expressed it as there's a very important thing missing and that's Claudia. She's a big part of my life and that's not there any more and it's hard."
But he said that he and the rest of her family thought Miss Lawrence was "still around somewhere" and ended the video with an emotional direct appeal to her.
"Claudia, for whatever reason it was that you had to disappear, or you might not have known that reason, if you're there now and watching, please, please do get in touch with us. There's absolutely no reason why you shouldn't.
"All we want is you back. You're a great big missing part of all our lives at the moment."