A woman in her 30s has been arrested on Monday following the fatal shooting of Jason Doogue (22) in Athy, Co Kildare.
A teenage boy and a man in his 40s also remain in custody after being arrested over the weekend.
All three are being detained under Section 50 of the Criminal Justice Act, 2007, and can be held for up to seven days without charge.
A younger teenage boy who was also arrested on Saturday has been released without charge from Leixlip Garda Station.
Jason Doogue was shot three times in the chest outside his home in Greenhills at approximately 5pm on Friday.
The young man was sitting on the wall outside his home chatting with a group of friends when a gunman on a BMX bicycle approached him. The gunman, wearing a balaclava, fired directly at Mr Doogue.
The victim fell backwards over the wall and the gunman then leaned over the wall and discharged two further shots at him before leaving the scene.
Emergency services were called and Mr Doogue was taken to Naas General Hospital for emergency surgery, but was pronounced dead less than two hours later.