Four men arrested in connection with the attempted murder of a Northern Ireland police detective have been released, but officers have been given more time to question two others.

Detective Chief Inspector John Caldwell is in a critical but stable condition in hospital, where he has been since he was shot in front of his young son in Co Tyrone on 22 February.

He was targeted at a sports centre in Omagh, where he coaches a youth football team.

On Tuesday night police said that four men aged 22, 38, 43 and 45 had been released following questioning.

A court in Belfast also granted detectives an extension until 10pm on Thursday to question a 47-year-old man, having earlier granted an extension until 10pm to question a 71-year-old man.

Both of them are in custody in the serious crime suite at Musgrave Police Station.

Police believe two gunmen were involved in the attack on Mr Caldwell, with at least 10 shots fired.

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They are also reviewing an unverified claim of responsibility from the New IRA.

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Police say ‘children ran in sheer terror’ after off-duty officer was shot

On Saturday, people gathered in the village of Beragh and in nearby Omagh to show their solidarity with Mr Caldwell.

Public appeals

Detectives want to hear from anyone with information, in particular anyone who saw a blue Ford Fiesta thought to have been used by the gunmen in the two weeks before the attack or immediately afterwards.

Images of the car were released by police on Monday.

The car’s registration number is MGZ 6242, but police said it was fitted with the false plate FRZ 8414 before the attack.

Independent charity Crimestoppers is offering a reward of £20,000 for key information that could aid the investigation.