Detectives in Northern Ireland were carrying out a manhunt today after a rookie police officer was killed by a booby trap car bomb.
Ronan Kerr, 25, had only spent weeks in the Police Service of Northern Ireland (PSNI) when the device exploded under the vehicle outside his home on the outskirts of Omagh, Co Tyrone, yesterday.
Dissident republicans opposed to the peace process are believed to have carried out the killing.
His murder was condemned by the British and Irish governments, Stormont, church leaders and cross-party representatives.
PSNI chief constable Matt Baggott said: "We have lost one of our brave and courageous police recruits, someone who joined this fine service simply to do good, joined to serve the community impartially and to be someone I describe as a modern-day hero."
He only graduated from training college last December.
The explosion happened as the officer got into his car in the residential Highfield Close development, off the main Gortin Road, yesterday afternoon.
The blast sent shivers through Omagh, where 29 people, including a woman pregnant with twins, were killed in the 1998 Real IRA car bomb attack.
It is understood the victim, a former pupil of the Christian Brothers Grammar School in Omagh, was leaving to start a shift at Enniskillen police station, Co Fermanagh, when he was killed.
Police Service of Northern Ireland (PSNI) temporary Superintendent Pauline Shields said: "He has literally been with us for weeks.
"In those few weeks that he has served this community he has made an indelible mark on those colleagues and those members of the public with whom he has come into contact."
Police are combing the area of the blast for clues about who was responsible.
Prime Minister David Cameron said the young officer had dedicated himself to serving the entire community of Northern Ireland.
"Those who carried out this wicked and cowardly crime will never succeed in dragging Northern Ireland back to a dark and bloody past," he warned.
"Their actions are rejected by the overwhelming majority of people from all parts of the community."
Irish Taoiseach Enda Kenny described the bomb attack as a heinous and pointless act of terror.
"Those who carried it out want to drag us back to the misery and pain of the past," he said.
"They are acting in defiance of the Irish people."
First Minister Peter Robinson urged young Catholics not to be deterred from joining the police "by those who have nothing to offer our society".
Deputy First Minister Martin McGuinness said the perpetrators had "betrayed the community" and had "no role to play in our future".
US secretary of state Hillary Clinton whose husband, former president Bill Clinton, played a major role in the peace process, said her government strongly condemned the murder in Omagh.
"The perpetrators of this cowardly act represent the failures of the past and their actions run counter to the achievements, aspirations, and collective will of the people of Northern Ireland," she said.
"We echo the unequivocal condemnations by Northern Ireland's politicians and call on anyone with information to co-operate fully and expediently with the Police Service of Northern Ireland."
Dissidents have carried out a string of similar attacks on Catholic PSNI officers in recent years.
Pc Stephen Carroll, 48, was gunned down in March 2009, just two days after the Real IRA shot dead two British soldiers at the Massereene Army base in Antrim.
And Pc Peadar Heffron was seriously injured when a device exploded under the driver's seat of his car in west Belfast in January 2010.