The spokesman for Claudia Lawrence's family said there was "still a long way to go" in finding out what happened to the chef.
Martin Dales said in a statement:
Today has been an exacting day for Peter, his family and Claudia’s friends as the news comes of the first arrest in the five years since she went missing.
It is clear that the renewed efforts of North Yorkshire Police since last autumn and the new information provided by the public could well be bearing fruit but we shall have to wait and see.
It is vital that information continues to flow and it is to be hoped that the events of today encourage the public to keep coming forward to the police.
Anyone with information should call 101 and select North Yorkshire police if not in their area.
More top news
The PM will promise today to unmask the corrupt offshore companies that are buying up luxury London properties using "plundered cash".
A public inquiry into undercover policing in England and Wales is to be formally opened today.
Lorries are being parked on the M20 again as a "heavy volume" of traffic heading for Europe led police to reintroduce emergency closures.