Dissident terror gangs have been described as criminals masquerading as republicans after the execution of a former paramilitary leader.
Tommy Crossan, a former chief of the Continuity IRA, was shot twice in the head and several times the body in the Good Friday gun attack in west Belfast.
The father-of-six, from the Falls Road, is believed to have been killed by former republican associates he had fallen out with.
His life was under threat after he was accused of stealing CIRA cash and being an informer.
At an Easter Rising commemoration at Milltown Cemetery yesterday, Sinn Fein MEP Martina Anderson hit out at the "small minority" of dissident factions trying to derail the peace process.
She said Crossan's murder was a senseless action, adding those responsible should go away.
"They are criminals masquerading as republicans no matter what names they attach to themselves," she said. "Their actions sully the name of republicanism.
"And as we prepared to gather at Easter time to commemorate our patriot dead, one of these small groups took the life of Thomas Crossan in this city."
It has been reported Crossan was building a new republican terror faction in recent months.
He was said to have been at the helm of the Irish Volunteers grouping, said to be behind a series of security alerts across Belfast in the past year.
A 26-year-old man was arrested by police on Saturday in connection to the murder and remained in custody last night. The detective leading the hunt for Crossan's killers said investigators were pursuing a number of leads to identify the gunmen.
The shooting happened just after 5pm on Friday on the busy Springfield Road. He was shot by up to three men, who fired through the window of an office he was in.
It is understood the shooting happened minutes before Crossan's daughter drove into the middle of the scene of his killing.
The day after the murder, masked terrorists launched a verbal attack on Deputy First Minister Martin McGuinness, calling him a "traitor to Ireland".
The CIRA split in 2010 amid the allegations against Crossan and close friends. He had been one of the terror faction's highest-ranking members.
In 1999 he was jailed following a gun attack on Woodbourne RUC station.
Following his release he became involved in CIRA activity again. In 2008 he and another man were convicted of trying to extort £50,000 from a Dungannon businessman. Crossan received a suspended sentence, while the other man, Martin Overend, was sentenced to nine years.
Crossan's former paramilitary allies launched scathing criticism of Mr McGuinness at an Easter Rising commemoration in Lurgan the day after the killing.
A spokesman for Republican Sinn Fein said: "It seems to me that Martin McGuinness is everything that's wrong with Ireland."
Dissident republican Tommy Crossan was shot dead while he sat in an office.
A 26-year-old man was arrested in connection with the killing of the 43-year-old father-of-six who was a former senior member of the Continuity IRA.
He was gunned down at a fuel depot in the grounds of an industrial complex in full view of surrounding houses.