The 42 year-old was detained in north Belfast on Monday night.
A 42-year-old man arrested by detectives investigating the murder of a prominent paramilitary has been released unconditionally.
Ulster Defence Association (UDA) member John Boreland, 46, was shot several times with a shotgun outside his apartment in north Belfast on Sunday night.
Detectives believe the shooting of the known criminal was linked to disputes between rival loyalist factions.
The man spent a day in custody following his arrest in north Belfast on Monday night.
Mr Boreland, a father of three, survived a murder bid in 2014 and had been made aware of a death threat in recent weeks.
There have been mounting tensions between loyalist gangs in north Belfast in recent weeks. Loyalist gunmen have been responsible for dozens of murders since the organisations supposedly went on ceasefire in the 1990s.
Many killings have been linked to feuds and turf wars among rivals and the latest shooting has prompted further questions about the authenticity of the ceasefires.
Last year, the main loyalist paramilitary groups restated their commitment to non-violence as they came together to launch a new initiative - the Loyalist Communities Council.

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