The deaths of two men found in separate flats in the same block are linked and both were murdered, police revealed.
The bodies were found in the complex in Waterford Drive, Chaddesden, Derby, several days apart.
John Matthews, 66, known as Dave, was found in his flat last Sunday evening after his employer raised concerns when he did not turn up for work.
Murder inquiries led to the arrest of a man in Cumbria on Friday morning.
A few hours later a second body was found in another flat in the same block when officers became concerned that there was no answer to their knocking.
The Derbyshire Police confirmed both men had died of knife wounds.
The second man was expected to be named on Monday, once his next of kin have been informed.
A spokesman said: "A police presence remains in Waterford Drive with further examinations and searches of the scene and areas leading to and from the flats."
On Sunday police released a picture of Mr Matthews, who worked part-time as a kitchen porter in Darleys restaurant in the city, in a bid to trace his last movements. Assistant Chief Constable Steve Cotterill said he was last seen on Friday July 9 at work.
A 47-year-old man, from Derby, arrested on suspicion of murder by Cumbria Police in Whitehaven on Friday remained in custody. On Sunday Kathryn Hobson, owner of Darleys, paid tribute to Mr Matthews, whom she said staff affectionately called "Grandad".
