DCI John Caldwell was shot in front of his son by masked men in Northern Ireland (Picture: PA)

Police have released images and CCTV of a Ford Fiesta used by suspected New IRA gunmen who shot a senior detective in Northern Ireland last week.

DCI John Caldwell was hit multiple times in front of his young son when two masked men fired 10 bullets at him in a sports centre car park in Omagh, County Tyrone, last Wednesday.

The dissident group has made an unverified claim of responsibility and police are treating its members as their main line of inquiry.

Six men aged between 22 and 71 are being questioned in custody, while a £20,000 reward is being offered by Crimestoppers to anyone with key information.

Detectives are urging anyone who saw the car in the two weeks before the attack to come forward.

It is known to have been bought in Northern Ireland and was left to burn near Omagh as the gunmen fled, possibly before crossing the border.

Detective Chief Superintendent Eamonn Corrigan said: ‘Our CCTV footage shows the car leaving the sports complex and turning left on to the Killyclogher Road immediately after the shooting. We then know it travelled past Glendale Service Station to the Racolpa Road where they abandoned the car and set it on fire.

Detectives believe people may know where the car was stored in Belfast and Omagh (Picture: PA)

‘We have established that the car was purchased in Ballyclare on Wednesday February 8 and was observed travelling towards Belfast on the M2 motorway that night.

‘It was next noted leaving Belfast at around 9.30pm on Tuesday February 21 – the night before the attack on John – and travelled along the M1 motorway in the direction of Coalisland/Omagh.

‘My appeal today is for anyone who knows where this car was kept in Belfast in the preceding two weeks or anyone who knows where it was stored after it travelled to Omagh on the Tuesday night.’

The car was bought with registration number MGZ 6242 and it was fitted with fake plates reading FRZ 8414 at some point while it was in Belfast, he adedd.

The car has a distinct alloy wheel which could help identify it (Picture: PA)

DCI Caldwell remains fighting for his life in a stable but critical condition in hospital.

On Sunday night, a typed message was taped on a shop wall in Londonderry signed by ‘T O’Neill’, a name previously used by the New IRA.

It said: ‘The Irish Republican Army claim responsibility for the military operation targeting senior Crown Force member John Caldwell.

‘An active service unit of the IRA were in position to target the enemy within our chosen kill zone with other armed volunteers giving cover. All volunteers returned safely to base.

‘Irish Republican Army intelligence are now in possession of security information regarding the out of bounds movement of Crown Force personnel.

‘We would say this, you still have to try and live a normal life day-to-day, one of these days the IRA will be waiting.’

Get in touch with our news team by emailing us at [email protected].

For more stories like this, check our news page.

A Ford Fiesta with distinctive features was bought in Northern Ireland and burned by a roadside as the attackers fled.