James McConnell, 38, was gunned down by two masked men in his home in the Woodland Avenue area of the city in February 2009.
The suspect was arrested in Dungiven and has been taken to the PSNI's Serious Crime Suite at Antrim police station.
The man is also being questioned about a shooting incident in the village of Feeny in Co Derry in 2004, when a shotgun was fired at a house.
Detectives have also undertaken two searches in the Dungiven area.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? firstname.lastname@example.org