The man arrested on suspicion of murdering a Dublin woman at the weekend was well-known to her.
The 27-year-old remains in Garda custody this morning in relation to Sandra Boyd's death.
The 36-year-old mother-of-five died on Saturday night, after being shot at her family home in Finglas.
John Hand, the chief reporter with the Irish Daily Mirror, says the suspect, who was arrested yesterday, can be held for seven days.
"He is well known to the victim.
"He was one of a number of people present at the gathering at the time and detectives are continuing to try and establish if the suspected gunman had the firearm, and Sandra was shot accidentally in the process of disarming him.
"This man was located and arrested - it's understood he was he had presented himself into St. James's Hospital on Sunday for treatment."
