DUBLIN -- A former Irish Republican Army commander linked to one of the outlawed group's most notorious killings was shot dead at close range Tuesday morning on a street near his home in Belfast, residents and police said.

No group claimed responsibility for killing Gerard "Jock" Davison, 47, in Belfast's Markets neighbourhood. It was the first fatal shooting in Northern Ireland in more than a year.

Officers ordered an immediate increase in visible street patrolling, including road checkpoints, to deter what they called a rise in attacks by IRA die-hards in the run-up to Thursday's United Kingdom general election involving Northern Ireland, which has 18 seats in the House of Commons in London. Small IRA factions who reject their side's 1997 cease-fire and subsequent efforts to govern Northern Ireland in a spirit of compromise have planted several bombs in the past two weeks, none of which caused significant damage.

But the policeman leading the Davison murder investigation, Det. Chief Inspector Justyn Galloway, said he doubted that an IRA splinter group was responsible. He also dismissed involvement by extremists from Northern Ireland's British Protestant majority, meaning that his killers more likely had a criminal or personal motive.

"This was a cold-blooded murder carried out in broad daylight in a residential area and it has no place in the new Northern Ireland," Galloway said.

The relative rarity of Tuesday's killing underlined how much has changed in Northern Ireland from the bloodiest years of its four-decade conflict that left more than 3,600 dead in a British territory of 1.8 million.

Negotiators delivered a 1998 peace accord that forged a Catholic-Protestant government with the IRA-linked Sinn Fein party at its heart. British troops have been off the streets for nearly a decade, Protestant militants who used to kill Catholic civilians at random in retaliation for IRA attacks have stuck to truces, and the once Protestant-dominated police force has become increasingly Catholic in membership.

Sinn Fein voted in 2007 to start co-operating with British law and order, a stunning U-turn reflected in the party's appeals Tuesday for Markets residents to tell detectives what they knew about the killing.

It's a rich irony, given that IRA veterans like Davison long enforced the opposite policy, particularly when it concerned their own members' crimes. As the top-ranking IRA figure in the Markets, he wielded an authority that included the right to shoot criminal opponents in the limbs and to use intimidation to shield the IRA's own members from arrest -- including by killing any local identified as a police informer.

Davison in 2005 allegedly ordered IRA comrades to attack a Catholic civilian, Robert McCartney, at a pub near the Markets following an exchange of insults. Nobody was ever successfully prosecuted for the fatal stabbing, which happened in front of dozens of witnesses.

Defying the IRA's code of silence, McCartney's widow, his mother and four sisters took their demands for justice all the way to the White House, winning support from Hillary Clinton and the late Sen. Edward Kennedy. Their unprecedented campaign helped spur the dominant IRA branch, the Provisionals, to renounce violence and disarm later that year, followed by Sinn Fein's vote to accept the legitimacy of Northern Ireland's criminal justice system.

McCartney's sisters accused Davison of making a throat-slashing gesture to his IRA colleagues before McCartney, 33, was chased outside the pub and killed. IRA members confiscated the pub's surveillance video footage, cleaned up forensic evidence and ordered pub-goers to tell police nothing or risk IRA retaliation, according to police and court testimony.

Davison was arrested on suspicion of ordering the killing but was not charged. Two others, including his uncle Terence Davison, were charged with McCartney's murder but were acquitted in 2008.

IRA representatives met McCartney's widow and sisters and offered to have the IRA members responsible killed as punishment, an offer the women rejected. The IRA and Sinn Fein later expelled or suspended three IRA members and eight Sinn Fein members over their alleged role in the assault or coverup of evidence.

Gerard Davison always denied involvement in the McCartney attack, insisting he tried to act as a peacemaker when McCartney and McCartney's friend Brendan Devine got into an argument inside the pub with Davison's uncle and IRA members at his table.

Davison's body lay in the street Tuesday until police constructed a tent around the victim to protect forensic evidence. Residents said at least some of Davison's three children saw their father lying dead and ran home screaming.

Sinn Fein official Alex Maskey said his party wouldn't speculate on who killed Davison or why. He called Davison "a longstanding republican" who was "very well regarded."