Two of the four people arrested yesterday in connection with the murder of Baiba Saulite last year are still being held for questioning today.
Two men and two women were arrested in Dublin and taken to Coolock, Raheny, Santry and Swords Garda stations for questioning under Section 30 of the Offences Against the State Act.
The women, both aged 20, have since been released without charge. Files are being prepared for the Director of Public Prosecutions.
The men, who are aged 19 and 23, remain in custody in Coolock and Swords Garda stations. They can be held for up to 72 hours before being charged or released.
Ms Saulite (28), who was originally from Latvia, was shot dead at the doorway of her home in Holywell Square, Swords, Co Dublin on November 19th, 2006, as her two children slept upstairs.