Daniel McGurk: Murder victim
Three men and a woman have been arrested by detectives investigating the murder of a father-of-six in west Belfast.
Daniel McGurk, 35, was shot dead at his home in Ross Road in the nationalist lower Falls area on Sunday, after he opened his door to gunmen.
Dissident republican paramilitaries have been blamed for the killing, but police have said they are keeping an open mind about the motive.
On Tuesday, the police said a number of searches had been carried out in west and south Belfast.
A rifle, a number of handguns and a quantity of ammunition were recovered in the Beechmount area.
A number of items have also been taken away for forensic exmamination.
Earlier, the Ulster Unionist leader, David Trimble said the murder was a sign
the situation in Northern Ireland was unstable.
He said it was a tragedy for Mr McGurk's family, but also showed that Sinn Fein's position on policing was harming its own community.
Speaking on the BBC Radio Four's Today programme, Mr Trimble pointed out that the policing situation had not yet been resolved.
Sinn Fein has not yet signed up to the Policing Board.
"The situation that mainstream republicans have got themselves into of inching towards support for policing but not being able to go the whole way is not a satisfactory state of affairs," said Mr Trimble.
However, Sinn Fein chairman Mitchel McLaughlin, hit back at Mr Trimble accusing him of a "cynical attempt of political point-scoring".
He added: "Mr Trimble also ignores loyalist violence emanating from within
his own community.
"In the past number of years the various unionist paramilitary gangs have
carried out violent campaigns against Catholics and engaged in feuds with each
On Monday, Mr McGurk's mother, Mary, 73, said her son was killed because he had stood up to "thugs and drug dealers".
David Trimble: Murder was "tragedy for family"
She appealed for no retaliation for the killing.
Detective Superintendent Hugo Frew of the PSNI said it was a cold-blooded murder.
He said the possible involvement of dissident republicans was being looked at.
Northern Ireland Office minister John Spellar condemned the murder as "cowardly and barbaric".
West Belfast MP Gerry Adams said Mr McGurk had been the "victim of gangsterism and thuggery".
SDLP councillor Margaret Walsh said she had been told the man was threatened by dissident republicans last week.
The Police Service of Northern Ireland came into being in November 2001 as part of sweeping reforms to the service under the terms of the Good Friday Agreement.
The 19 member Policing Board, which includes politicians from the UUP, SDLP and DUP, along with independent members, was set up to hold the service to account.
Sinn Fein is the only party which refuses to endorse the new service.
The party has also refused to nominate members for the Policing Board because it believes present structures and reforms fall short of the Patten report.