Five people have now been arrested as part of the investigation into Mr Ryan's murder
One of three people being questioned about the Vincent Ryan murder has been released without charge.
The man was released late last night and a file will be sent to the Director of Public Prosecutions.
A man and a woman remain in garda custody in connection with Vinny Ryan's murder on 29th February in Finglas.
Mr Ryan was 25 when he was shot dead in his car.
The woman was arrested last night. She is being held at Finglas garda station.
Gardaí are renewing their appeal for any witnesses to contact Finglas Garda Station on 01-666 7500, the Garda Confidential Line on 1800-666-111 or any Garda Station