A senior detective shot multiple times in front of his son at a football training session suffered life changing injuries, Northern Ireland’s Police Federation has said.

Detective Chief Inspector John Caldwell was gunned down on Wednesday night at a sports complex in Omagh, Northern Ireland.

Three men - aged 38, 45, and 47 - were arrested in Omagh and Coalisland, also in County Tyrone. They remain in custody.

A fourth man, aged 22, was arrested in the Coalisland area in the early hours of Friday morning, police later said.

Mr Caldwell remains in a critical but stable condition in hospital. He had surgery on the night of the shooting and it is understood the 48-year-old underwent further surgery on Thursday.

The Police Service of Northern Ireland (PSNI) said they were keeping an “open mind” as to the motive behind the attack but said its “primary focus” was on violent dissident republicans and the New IRA.

Liam Kelly, the head of the police federation, said Det Ch Insp Caldwell was always looking to give back to society, the BBC reports.

"He's been involved in coaching with children over a long period of time and this is how he's been rewarded by terrorists - it's an absolute disgrace," he added.

Mr Caldwell is believed to have got up after being shot four times and warned children away from the area.

Some of the children who were waiting to be picked up by their parents after the football session “ran for cover in sheer terror” when the shooting began.

The headteacher of Omagh High School, where Mr Caldwell was a former pupil, said a number of students who witnessed the attack were “experiencing a huge degree of trauma”.

Mr Caldwell had been putting footballs in the boot of his car after coaching a session when masked two gunmen approached and opened fire.

Police believe the attackers fled in a small, dark car found burned and abandoned on Racolpa Road, outside Omagh.

Mr Caldwell is a high-profile officer who has led a number of major investigations, including taking a leading role in the murder case following the killing of Natalie McNally in Lurgan in December. He was also involved in the investigation into the murder of journalist Lyra McKee in 2019.

The New IRA was previously blamed for the killing of Ms McKee in Londonderry in 2019.

Last November, the group was thought to be behind the attempted murder of two police officers in a bomb attack in Strabane, Co Tyrone.

Omagh has seen significant dissident violence in the past, including a Real IRA bomb attack in 1998 which killed 29 people, including a woman pregnant with twins. It was also where Constable Ronan Kerr was murdered in April 2011.