A 26-year-old is still in garda custody this morning in connection with the murder of Latvian woman Baiba Saulite in north Co Dublin last November.
The man, who is believed to be an associate of murdered drug dealer Martin 'Marlo' Hyland, was arrested at his home in Finglas yesterday morning.
Ms Saulite, a 28-year-old mother-of-two, was shot dead at her home in Swords last November while her two young sons slept upstairs.
Gardaí believe the murder was a contract killing.
The man arrested yesterday is also reportedly implicated in another gun attack last year - the fatal shooting of Donna Cleary at a house in the Coolock area of north Dublin.