Perparim Malaj, 27, was stabbed to death in September 2001.
Mr Malaj, from Tropie in northern Albania, died following a fight on in Chapel Street, Luton.
Police inquiries in Bedfordshire uncovered a feud between two rival groups of asylum seekers and launched inquiries in the east European country.
On Thursday, an Albanian court found Petrit Coli, 30, guilty of Mr Malaj's murder and of trafficking in prostitution.
Two other men, Arben Pali, 25, and Marjan Lukaj, 25, were found guilty of murder and sentenced for 15 years in absentia, as they have never been arrested.
Detective Inspector Sean O'Neil said: "This case has proven that if a criminal from any background commits such an offence in the UK, then the resources of law enforcement will work in partnership to tackle the problems and bring the offenders to justice."
He thanked Albanian authorities for trying the case and UK witnesses for stepping forward.
Long feud
Police said the murder was a revenge attack after an earlier stabbing in Luton.
Bedfordshire police travelled to Albania after Coli had returned home to Shkoder and in July last year served a file on the Albanian Ministry of Justice.
Under international law, prosecutors there agreed to begin proceedings against the three men.
A fourth man, Azem Gashi, 30, faces deportation after he serves three-and-a-half years in UK prison after pleading guilty to facilitating the escape of the killers.