A third person has been arrested by gardaí investigating the fatal stabbing of a German man in Rialto yesterday morning.
The woman in her 40s was arrested in Dublin at 1pm this afternoon.
Gardaí are also questioning two teenagers in connection with the death of the 22-year-old, who was stabbed to death at the Herberton Apartments in Rialto.
A second man who was seriously injured in the attack is in a stable condition in hospital.
The woman arrested today is being detained in Pearse Street Garda Station.
The two men remain in custody in Kevin Street Garda Station.
Gardaí at Kilmainham have appealed for witnesses or anyone with information to contact them.