DCI John Caldwell: The senior officer who led several high-profile murder probes including the Omagh murder of PSNI officer Ronan Kerr

The killing of Constable Kerr was blamed on dissident republicans styling themselves as the New IRA - the same renegade group police suspect of shooting Detective Chief Inspector Caldwell on Wednesday night. Mr Kerr, a 25-year-old recently graduated police recruit, died when a booby trap bomb detonated under his car outside his home in Omagh in April 2011.

Making an appeal for information on the 10th anniversary of the murder in 2021, Mr Caldwell's words now assume a chilling poignancy given what happened to him in the same Co Tyrone town. "His job was to protect the community," he said. "Despicably, people living in his own community planned and plotted to kill him simply because he was a police officer bravely going out every day to protect people and make communities safer places to live and work."

Given the ever-present security risk, the PSNI strive to protect the identities of the majority of their officers in the public sphere. However, high-ranking officers do have more of a public profile and they often front media appeals related to major investigations.

Mr Caldwell is a familiar face on the TV news in Northern Ireland and is accustomed to giving press conferences and interviews. In December he was involved in the investigation following the murder of expectant mother Natalie McNally. Ms McNally, 32, who was 15 weeks pregnant, was stabbed at her home in Silverwood Green, Lurgan, Co Armagh.

Earlier in December, Mr Caldwell took on the case of Mark Lovell. The 58-year-old was shot a number of times at close range while in his car outside his home in Newry. A month later, the DCI assumed the role of senior investigating officer when Shane Whitla, a 39-year-old father-of-four, was shot dead in Lurgan, Co Armagh.

In October 2022, he headed the probe into the murder of Ryan McNab in Co Antrim. Mr McNab, 31, from north Belfast, was killed in an attack in the Rathcoole area of Newtownabbey.

In January of that year, Mr Caldwell fronted public appeals following the fatal stabbing of Martin Gavin, 47, in Belfast.

The previous year, Mr Caldwell led the probe into the murder of Katie Brankin, who was murdered by her partner at a glamping site in Limavady, Co Derry.