A teenager is amongst four people being questioned over the shooting of gangland enforcer Robbie Lawlor.
Crazed hitman Lawlor was shot at close range in the garden of a Belfast home yesterday morning.
The youth, 17, was arrested yesterday along with two men in their 30s, RTE reports.
A fourth man, aged in his late 20s, was picked up by PSNI investigators overnight.
All four are being questioned at Musgrave Police Station in Belfast and police say they are investigating a number of lines of inquiry.
Lawlor, 35, was basted dead at close range outside a house in the Ardoyne area of Belfast shortly before midday yesterday.
Garda had warned the north Dublin criminal, who had more than 100 previous convictions and was only released from prison in December, that his life was in danger before he travelled north to Belfast.
Lawlor was a suspect in a number of gangland killings - and was believed to be behind the Narcos style murder of teenager Keane Mulready-Woods.
The gruesome killing of the 17-year-old Drogheda boy, whose body was dismembered and dumped around north Dublin in January, shocked the nation and made headlines all around the world.
Gardai have been working closely with the PSNI as they investigate yesterday’s murder.
