Six people are being questioned today in connection with the murder of James Cronin, who was found shot in the head on waste ground in Limerick earlier this year.
Mr Cronin (20) was from the Ballinacurra Weston area of Limerick city.
The shallow grave containing Mr Cronin's body was found on April 7th by a team of gardaí searching for guns used in two shootings in the city during the preceding weekend.
Gardaí believe he was shot in a gangland dispute connected with the killing of Mark Moloney (40) in the Garryowen area.
Detectives believe Mr Cronin had supplied the vehicle used in a shooting in the city and was killed by those involved in that attack because they believed he was about to turn Garda informer.
Two men in their 20s, a youth (16) and three women, all in their early 20s, were arrested in the Ballinacurra Weston area yesterday evening.
They are being held under Section 30 of the Offences Against the State Act at Roxboro, Mayorstone, Henry Street and Askeaton Garda stations. They can be held for up to 72 hours before being charged or released.