Gardaí believe that attacks on the property of prison officers in Limerick over the past week are part of a campaign of intimidation.
A third attack on prison officers in Limerick occurred at the weekend, when two shots were fired in the vicinity of a house in the Raheen area of the city.
The house belongs to the same prison officer whose car was petrol-bombed during an overnight attack eight days ago.
Shortly after 1 a.m. on Sunday, residents in the area were awakened by the shots.
"My wife heard the two shots and she woke me up and we saw a car speeding from the area," one resident said.
"Neighbours around are very uneasy about the whole thing," he added.
The previous morning, seven cars in the area were broken into, although gardaí say this may be unrelated to the attacks on prison officers.
A hoax bomb left outside a second prison officer's home on the Shelbourne Road on Wednesday resulted in an Explosive Ordnance Disposal team being called from Cork.
The attacks have been condemned by the governor of Limerick Prison, Mr Pat Laffan, and the Prison Officers' Association.