Smash hit

"Andreas went back to his own flat and got a set of keys for Derek's apartment and eventually went round there at around 4pm.

"He told detectives he walked into the living room and saw Derek lying on his back on the floor. He described there being lots of blood, more than there would be from just a punch.”

Mr Langweider said: "All I will say is that Derek was my best friend and he was like a brother to me. He was the best person you can imagine and he is missed by so many people."

Mr Cowan, who lived with his Spanish girlfriend, was a partner in United Companies and Associates.

On the Friends Reunited website, Mr Cowan wrote on his profile page: “Have travelled extensively, living in London, Manila and now settled (for the time being) in Barcelona.

“Living with Spanish girlfriend and working as a currency trader in the sun.”

He attended Lanark Grammar School and Larkhall Academy in Lanarkshire, according to his entry on the site.

John Irvine, 46, a close friend of Mr Cowan, said: “He was a very likeable character, very good fun, entertaining and sociable. He was good-hearted through and through and very close to his friends.

“It is a terrible thing that has happened. It was a shock for all who knew and cared about him. I’m absolutely shattered with it.”

Mr Irvine, who runs a scaffolding firm in Hamilton, Lanarkshire, added: “He had a nice lifestyle in Barcelona and I’m not aware of him having any problems. He always sounded very positive.”

He said Mr Cowan was abandoned as a baby and brought up in an orphanage before being fostered by a family in Larkhall, Lanarkshire. He recently found his natural mother and half-brother and sister in London.

“He had a pretty unfortunate beginning and a tragic end but he did more living than a lot of people,” said Mr Irvine. No arrests have been made.

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