Eight of the people arrested on Friday in relation to the New IRA attempt to kill PSNI detective John Caldwell are understood to be from a Protestant background.
Mr Caldwell (48) was left fighting for his life after being shot at the Youth Sport Omagh complex on the Killyclogher Road in February.
He remained in critical condition for several weeks but was released from hospital last month.
He was pictured attending a garden party at Hillsborough in Co Down this week and held a private meeting with King Charles.
A claim of responsibility for the New IRA attack was posted on a wall in Derry shortly after the attack.
Around 10 rounds were fired at Mr Caldwell by two gunmen as he packed footballs into his car after a youth soccer training session.
It is understood that a revolver and a 9mm handgun were used in the attack.
A total of 11 men and women were arrested in a series of raids in the Coalisland and Omagh areas on Friday morning.
It is believed seven of the suspects were previously arrested.
Eight of those being held are understood to be from a Protestant background, including two women.
It is thought several of those detained are members of one family.
They include a 72-year-old man, who was previously arrested, and a number of his sons.
Another man, who was also previously arrested, is also believed to have been detained with his son on Friday.
Ten of the arrests were made in the Omagh area, with one person detained in Coalisland.
Those re-arrested include five men in Omagh aged 33, 47, 45, 72, 28.
A 38-year-old man was detained in Coalisland, while a previously arrested 34-year-old woman was lifted in Omagh.
One of two men arrested in connection with the probe last week and later released is also believed to be among those detained on Friday.
Others arrested in Omagh include a woman, aged 52, and three men aged 29, 21 and 34.
The 72-year-old was one of eight men originally arrested in March.
At a press conference in Belfast yesterday, Detective Chief Superintendent Eamonn Corrigan released CCTV images and appealed for information about of a number of vehicles involved in the attack – a Mercedes and two Ford Fiestas.
“John is making a really good, steady recovery compared to where we were the night he was shot, when we in the investigation team feared that he would die and it was treated as a potential murder from the beginning of the investigation,” Mr Corrigan said..
“So, John is making a good recovery and we were all delighted that he was well enough to attend the party.”
And he added: “Now we need to make sure we bring those vile individuals who tried to murder him to justice.”
