A 60-year-old man arrested on suspicion of murdering Claudia Lawrence, who has not been seen since she disappeared in March 2009, has been released without charge.
The man named locally as Michael Snelling was arrested in May and a property in York was searched.
Another man, a 46-year-old arrested on 23 July on suspicion of perverting the course of justice remains on police bail.
Lawrence worked as a chef at the University of York. She was meant to turn up for work on the morning of 19 March but never arrived.
Police have treated her disappearance since as murder.
A spokesman for the investigation said: "This remains a live investigation with new lines of enquiry being actively pursued."