Police in the North are investigating if the murder of senior dissident republican on Saturday is linked to the killing of Dublin criminal Robbie Lawlor.
They have described the murder of 28-year-old Warren Crossan in west Belfast as callous and reckless.
Crossan, who has significant links to dissident republicans, was shot a number of times in St Katharine's Road on Saturday.
He was chased by two masked gunmen through streets packed with people and motorists before he was shot dead.
His father Tommy Crossan was a prominent dissident republican and was shot dead at a fuel depot in Belfast on Good Friday in 2014.
Detective Chief Inspector Darren McCartney told reporters links to organised crime have not been ruled out and it is too early to speculate on a motive.
"This is a callous and reckless killing. Bringing firearms out into residential streets of west Belfast in broad daylight just beggars belief.
"The gunmen did not give any thought to the risk this posed to the residents and members of the public carrying out their everyday business in the area.
"One of these shots struck a vehicle belonging to a local resident and that just goes to show the callousness that these gunmen had.
"While it is too early to speculate on a motive for the murder, links to an organised crime element have not been ruled out.
"However, I must state that the investigation is at a very early stage. It will take its course and I will follow the evidence wherever it takes my team over the coming days."
It is understood one of the potential lines of inquiry is a link to the recent murder in north Belfast in April of Dubliner Robbie Lawlor.
Lawlor, 36, was gunned down outside a house in Etna Drive in Belfast in April.
Lawlor had previously been linked with the murder of teenager Keane Mulready-Woods in Co Louth in January.
Asked if police are co-operating with Gardai in the Republic of Ireland about this potential link, Det McCartney said: "It is a very early stage in the investigation but I am ruling absolutely nothing out at this time."
"We have investigations ongoing throughout the length and breadth of the country," he added.
Mr McCartney said Mr Crossan was "well known" to police and it is too early to speculate on the motive for his murder.
"Warren was well known to police and that is part of the strategy of the investigation as it goes on at this time but again - it is a very early time at the start of this investigation and we cannot make a speculation around what has happened and why Warren was murdered."