Two women and a man were questioned by the PSNI last night about the brutal murder of 15-year-old schoolboy Thomas Devlin.
They were arrested at locations in north Belfast by detectives from the PSNI's Crime Operations Branch.
Thomas ,was stabbed to death close to his north Belfast home in August 2005. He was knifed up to five times in the back as he walked back along Somerton Road from a garage.
Much of the police inquiry has centred on Mount Vernon, a loyalist housing estate on the northern edge of the city.
One of the woman being held was arrested there yesterday. The other was detained in the Whitewell district while the man was taken in later.
With detectives believing the killers may have come from Mount Vernon, they seized items during searches of a property in its Ross Court complex on Monday.
During an earlier probe there police brought in a specially-trained sniffer dog. That was prompted by the discovery of a knife nearby. The weapon has since undergone forensic tests.
The latest arrests bring to 15 the number of people held as part of the inquiry.
No one has yet been charged with the murder.
All three of the latest suspects were taken for further questioning at a special serious crime suite in Antrim.
PA