A man has been arrested in Spain in connection with the murder of a man found strangled at a Surrey racecourse more than four years ago.
Surrey Police said the 36-year-old man was detained by Spanish officers on Sunday in Barcelona.
Sukhwinder Singh, a father-of-three, was found dead in the car park of Epsom racecourse in 2006.
Officers are also looking for a second man in connection with the killing who is also believed to be in Spain.
Det Supt Jon Savell said: "The arrest of the man in Spain is a significant development in this long-running investigation which continues while he has been released on bail.
"We are still making every effort to trace a second man and will continue to rigorously investigate this case until we can bring those responsible to justice."
Mr Singh, an Indian national, attended a party in south London the night before he died.
Police suspect the death might have followed an incident at the party in a flat in Sandfield Road, Thornton Heath.
The victim's body was found by two members of the public at 0700 GMT on 21 January 2006.
Mr Singh was married with three daughters and came from the Punjab. He moved to Britain to work and be able to send money back to his family.
The man arrested in Spain was released pending further inquiries by detectives in Surrey.