The death of a man, whose body was found in a house on Teesside, is being treated as suspicious, say police.
Lewis Welch, 32, was found in Wheatacre Close, Marske, shortly before 1900 BST on Saturday 14 August.
Police arrested two men in connection with the death and later released them on bail.
A post mortem failed to establish the cause of Mr Welch's death, but detectives suspect the man may have taken drugs.
House visit
Mr Welch, who was single, had returned to the UK on Friday after a spell working abroad with the oil industry.
Acting Det Sg Mike Harper said: "We are keen to trace anybody who had been in contact with Mr Welch since his return to the UK.
"We are particularly interested in speaking to anyone who may have been with him during the day on Saturday and to anybody who visited the house in Wheatacre Close."
Further tests are being carried out to try to establish the cause of Mr Welch's death.