A second man has been arrested in connection with a fatal stabbing in Cavan on Saturday.
Supt James Coen also said that Interpol were assisting gardaí with their investigation.
However, he said they were particularly anxious to talk to anyone who was in the Connolly St area of the town between 11pm on Saturday and 12.30am on Sunday.
Two men forced their way into an apartment in Connolly Court on Connolly St just after midnight on Saturday night/Sunday morning.
Inside they attacked a Romanian man who had just moved to Ireland, stabbing him several times. He died shortly afterwards.
Two men in their 30s are still being questioned by gardaí in relation to the incident.
Supt Coen said gardaí were aware of claims that a brothel was operating in the apartment block.
It was one of many areas being investigated, he said.
He declined to comment in detail about reports suggesting the murder may have been a case of mistaken identity, saying gardaí were in the early stages of their investigation.