Four men and a woman have been arrested in connection with the attempted murder of Derry man Paul McCauley who was left in a coma after a sectarian attack in the Waterside area of the city more than five years ago.
Police say the three men arrested in Derry are aged 22, 42 and 49. The woman is aged 40.
They were detained at houses in the Fountain estate and Kilfennan areas of the city.
Three houses were searched in Derry as part of the operation.
A fourth man was arrested in the Midlands area of England and is aged 24.
Mr McCauley has been in a coma since he was attacked in the early hours of July 16, 2006.
He was attending a summer BBQ at the rear of a house in Chapel Road.
At 3.20am only he and two others remained when a group of up to 15 people came out of bushes and attacked them. After the assault the group made off in the direction of Irish Street.
The Independent Monitoring Commission later said the attack was carried out by UDA elements.
The attack left Paul requiring round-the-clock care and unable to communicate with his family, except by blinking his eyes occasionally.
To date only one person has been convicted in connection with the attack.
Police say the investigation remains active and ongoing. Detectives have again appealed for those with information about what happened that night to come forward and talk to police.