Claudia was last seen leaving the University of York's Goodricke College
A man has been arrested for posting a bogus message on a social networking site claiming to be missing North Yorkshire chef Claudia Lawrence.
The message was posted on a Facebook page dedicated to the case of Miss Lawrence, 35, who has been missing from her York home since last March.
An 18-year-old was arrested in Didcot, Oxfordshire on Wednesday morning and cautioned by police.
Miss Lawrence's father Peter said he was still "upset" by the incident.
The message, posted on Facebook on 9 November, read: " "Hi everyone just let you be aware that I am ok and I am safe and sound. Speak to you all soon. Claudia xxx"
Police said the man was released after being cautioned for making a malicious communication and wasting police time.
Speaking as he marked the 11 month anniversary of his daughter's disappearance, Mr Lawrence said he had not received an apology from the man.
He added: "I am pleased there has been a resolution to it but it was very distressing at the time.
"The police have managed to find out who it was but they had to waste a lot of time on it when they could have been doing something more valuable.
"It has upset me. It is a terrible thing for someone to do."
Police are treating Miss Lawrence's disappearance as suspected murder.
Det Supt Ray Galloway, who is leading the investigation, said: "The posting of this Facebook message, claiming to be Claudia Lawrence, caused significant anxiety and distress to Claudia's family and also diverted valuable police resources to pursue a line of enquiry that had no value."
Miss Lawrence was last seen leaving the University of York's Goodricke College, where she worked, on 18 March.
Mr Galloway added: "The investigation into the suspected murder of Claudia Lawrence continues and will do so whilst there are positive lines of inquiry to pursue."