A woman in her late 30s has been arrested by gardaí in Limerick city as part of the investigation into the murder of Jeffrey Hannon in 2007.
She is being detained at Henry Street Garda Station under Section 30 of the Offences Against the State Act.
19-year-old Mr Hannon from Southill was found dead in the O'Malley Park estate in November 2007.
He had a number of injuries to his body and had suffered head injuries.
18 people have been arrested to date as part of the investigation.
