Gardaí investigating the death of a man in his 50s in Tralee believe there may have been an altercation during a social gathering at the apartment where he sustained his injuries.
Two men have been arrested after the victim, who suffered serious injuries in the apartment in Co Kerry, died.
Shortly after 7pm on Sunday, gardaí and emergency services attended the apartment in the Abbey Court apartment complex, Tralee, where they found the injured man, who was pronounced dead at the scene a short time later.
One line of inquiry is that a row broke out, perhaps over an uninvited guest joining the gathering, and the victim was fatally stabbed.
Detectives are trying to piece together the events in the property and have spoken to several people present.
It is understood significant progress has been made in the case and a definite line of inquiry is being pursued.
A man in his 50s was arrested on Sunday in relation to the incident and was being questioned under section four of the Criminal Justice Act, 1984, at Tralee Garda station.
On Monday gardaí said a man in his early 30s had also been arrested and was being questioned at Killarney Garda station.
Gardaí are confident the results of the interviews being conducted, combined with forensic evidence being gathered at the scene, will result in a breakthrough.
The local coroner has been notified and the services of the State Pathologist and Garda Technical Bureau have been requested by investigating gardaí.
The body of the deceased remained at the scene, which has been preserved, on Monday morning.
A technical examination of the scene and a postmortem examination were to be conducted on Monday morning.
An incident room has been established at Tralee Garda station and an initial case conference has been held by investigators.
A spokesman for gardaí said local officers were investigating all of the circumstances surrounding the death.
Gardaí have appealed for witnesses, particularly to those who were in the vicinity of Abbey Court apartments and the Denny Lane/Street areas between 6.30pm and 7pm on Sunday, to come forward.
Anyone with information is asked to contact Tralee Garda station on 066-710-2300 or the Garda confidential line on 1800-666-111.