The PSNI says the New IRA remains its "primary focus" in the investigation into the shooting of off-duty police officer John Caldwell after reports emerged that some of those arrested are from Protestant and loyalist backgrounds.

"We know there is some speculation about the motivation behind the shooting incident because of the community background of some of the people who have been arrested," PSNI Assistant Chief Constable Mark McEwan said on Thursday, March 2 during a Northern Ireland Policing Board meeting.

"The individuals who people are speculating about are involved in criminality. They have quite strong and long associations with violent, dissident republicans, namely the New IRA, members of the New IRA.

"We are very clear that this is still assessed as being an attack being carried out by the New IRA and that's where the primary focus of the investigation is at this point and it is not related to some of the other speculation we have seen today."

Sinn Féin MLA Gerry Kelly, a member of the Board, asked McElwan if there is believed to be "a loyalist connection" to the attack.

"We shouldn't get confused with titles like loyalism," McElwan replied.

"These are people who are involved with criminality, they have strong links to members of the New IRA. Those are longstanding links.

"They've been arrested because we suspected they have been involved in this and we still assess that this has been an attack carried out by the New IRA who have very explicitly stated that they wish to carry out attacks on police officers."

Kelly's questions were posed after reports emerged that those arrested in connection to the shooting of Caldwell were from Protestant and or loyalist backgrounds.

According to RTÉ on Thursday, "Four of the eight men arrested as part of the investigation are from a Protestant and loyalist community background. They are not believed to have loyalist paramilitary connections."

Four suspects, aged 22, 38, 43, and 45, were released on Tuesday, February 28 after questioning, police said, while another suspect, a 71-year-old, was released on Wednesday night, February 1.

As of Thursday, March 2, a 47-year-old man who was arrested last week remains in police custody, as do two men, aged 33 and 57, who were arrested in Omagh and Belfast on Wednesday.

On Wednesday night, February 22, PSNI Detective Chief Inspector John Caldwell was shot multiple times by two gunmen as he loaded footballs into the boot of his car at the youth sports center on Killyclogher Road in Omagh, Co Tyrone.

Caldwell remains in a critical but stable condition following last week's attack, which police say was carried out in front of his teenage son and a number of other witnesses. 

On Monday, PSNI released CCTV footage of the car, a blue Ford Fiesta, used by the gunmen.

As the PSNI continues to appeal for information, the independent charity Crimestoppers has offered a £20,000 reward for any information that leads to the arrest and conviction of those who carried out the attack.