Detectives from Serious Crime Branch investigating the murder of Paul McCauley in Derry in 2006 have arrested a 25 year old man in the city.
He has been taken to Strand Road police station for questioning.
Detectives say today's arrest brings the number of people who have been arrested since Paul died last June to 12.
To date, one man has been charged with murder and another reported to the Public Prosecution Service.
DCI Harvey said police enquiries into Paul’s murder were active and ongoing and he appealed to those with information to come forward.