All four are believed to be in their 20s.
Four people have been arrested by Gardaí investigating the armed robbery of a filling station at Tinryland, County Carlow.
During a follow up operation shortly after 9am on Thursday, Gardaí from Carlow Garda Station, assisted by the Armed Support Unit, carried out a search at a house in Carlow town.
Three men and one woman, all understood to be in their 20s, were arrested. They are currently detained under Section 30 of the Offences against the State Act, 1939 at Carlow Station.
The incident, which occurred in the early hours of Wednesday morning, saw two men, one armed with a gun and the other with a knife, enter a filling station at Tinryland (on the M9 at Junction 5) and threaten staff.
One shot was fired during the course of the raid, which happened shortly after 2.30am. The men made off in a dark coloured Volkswagen Golf with a small sum of cash. No one was injured during the incident.
All four are due to appear before a sitting of Carlow District Court on Friday morning, charged in connection with the case.
Gardaí are appealing to anyone in the filling station or the surrounding area between 2:00am - 2:30am to come forward with information by contacting Carlow Garda Station on 059 913 66220 or the Garda Confidential Line on 1800 666 111.
