Three men arrested on suspicion of murdering York University chef Claudia Lawrence have been released on police bail, North Yorkshire Police announced on Thursday (23 April).
The men, who are all in their 50s and from the York area, were arrested on Wednesday (22 April), and were released from custody in order "to allow detectives time to follow up lines of enquiry."
Their arrests followed the arrest of another man aged in his 50s on 23 March. He remains on police bail while enquiries continue.
Lawrence, who was aged 35 when she disappeared, was last seen on 18 March 2009. Friends raised the alarm when she failed to turn up for a 6am shift at the University of York the next morning. Her body has never been found.
Senior investigating officer Det. Supt. Dai Malyn repeated his request for the media and members of the public to refrain from identifying any of the men, as publishing their identities could cause "serious harm" to the investigation.
Miss Lawrence's family have been informed and are being supported by police.
In 2013 North Yorkshire Police launched a review of the case and two men were arrested.
One, aged 60, was released without charge. The other, aged 47, was arrested on suspicion of perverting the cause of justice, and was later released from bail.