Detectives have arrested a 32-year-old man on suspicion of murdering architect Joanna Yeates.
The suspect was detained in the early hours of Thursday after police investigating the 25-year-old's death uncovered fresh evidence.
Soon afterwards specialist search teams moved into the neighbouring flat to where Miss Yeates lived at 44 Canynge Road in Clifton, Bristol.
Dutch architect Vincent Tabak, 32, is registered as living at the address with his girlfriend Tanja Morson.
Calls to his employers in Bath were referred to Avon and Somerset Police. The force has not named the suspect, who is being held at an undisclosed location.
Workers erected scaffolding and green tarpaulin at the rear of the substantial converted Victorian property. The screen covers the entrance to flat two, where Mr Tabak lived, and the rear of Miss Yeates's rented home. Police sealed off both ends of Canynge Road as officers in white forensic outfits arrived at the property.
Miss Yeates's father welcomed the latest development, which came almost five weeks after she disappeared. Speaking at the family home in Ampfield, Hampshire, David Yeates, 63, said he was "pleased" the police investigation was "moving forward".
He said: "We know as much as you do. We were told at 6am this morning that someone was arrested on suspicion of Jo's murder and their age."
Detective Chief Inspector Phil Jones, who is leading the inquiry, thanked Miss Yeates's family and boyfriend for their support.
He said: "I would like to thank the public for their continued support for the investigation and the information they have provided to us. I would also like to pay tribute to Jo's family and to Greg, who continue to be unfailing in their support to me and my team at what is an incredibly difficult and painful time for them."