Two more people have been arrested in Limerick as part of the investigation into the murder of 25-year-old Gary Grant who was shot dead in the St Mary's Park estate last night.

The elderly couple, an 81-year-old man and a woman in her 70s, are being detained under Section 30 of the Offences Against the State Act at the city's Mayorstone Garda Station.

A handgun and a loaded magazine were found during the course of a number of follow-up searches in the St Mary's Park area late this afternoon.

The 20-year-old man arrested last night is still being held for questioning as part of the same murder investigation.

Mr Grant, a father of three children, was shot on St Ita's Street in St Mary's Park estate at around 10.15pm last night as armed detectives were patrolling the streets nearby.

He was rushed to the Mid-Western Regional Hospital in Limerick but died on admission.

Gardaí today launched a murder inquiry and are conducting house-to-house inquiries in the estate to try to establish exactly how the shooting happened.

The area has been sealed off and a technical examination was due to be carried out.