BELFAST, Northern Ireland (AP) _ Assassins struck for the second straight night in Belfast on Tuesday, killing a Roman Catholic man as he walked from his car to his front door.

No group claimed responsibility and police did not immediately identify the victim. But the killing adds tension to a Northern Ireland peace process already weighed down with suspicions.

The organized behavior of the killers _ they showed knowledge of the local Catholic turf, killed at point-blank and made quick escapes _ pointed to Irish Republican Army involvement, police and witnesses said.

In the first murder, Francis Collins was shot several times in his fast-food shop. His wife, Ann, was with him but was uninjured.

A caller claiming to be a spokesman for ``Direct Action Against Drugs'' claimed responsibility for Monday's killing. But police said the unknown group was probably a cover for the IRA, which is in month-15 of a cease-fire that follows 24 years of attacks against British rule.

Local witnesses said Collins' killers shouted ``Up the IRA!'' as they fled into the neighborhood.

Collins, 40, had been imprisoned for IRA offenses in the early 1980s but police said he ran criminal rackets in north Belfast after being paroled. Some locals connected him to drug dealing, though his wife denied the charge.

Tuesday night's victim had just stepped from his car outside his house when gunmen, who had held his family hostage waiting for him to arrive, shot him several times.

Collins' Catholic neighborhood in south-central Belfast is sandwiched between two predominantly Protestant districts. Until last year it was victimized by ``loyalist,'' or Protestant, gunmen, who called their own truce in mid-October 1994, six weeks after the IRA's.

Stunned locals dismissed suggestions that loyalists were behind the second killing.

``The `provies' done this. He must've done something to displease them,'' said a neighbor, too frightened to have her name used.

``Provies'' is street slang for the IRA, taken from its full name, the ``Provisional'' Irish Republican Army.

``It's very distressing. I thought we'd left all this behind us,'' said an ashen-faced Alasdair McDonnell, Belfast's first Catholic deputy lord mayor and a local doctor.

McDonnell arrived at the scene of Tuesday's shooting, which is about 100 yards from his medical practice, to find the man already dead in the street.

The killings come immediately after four days of fact-finding by an American-led commission tasked with recommending an acceptable way to disarm Northern Ireland's rival paramilitary groups.

Britain says disarmament must begin as a trust-building measure before the extremists' political representatives can join negotiations. The demand has stalled peacemaking efforts because neither side's paramilitaries are willing to give up guns as the price for talks.