Detectives investigating the murder of Finbarr Dennehy tonight arrested a man.
A 41-year-old was arrested in Dublin city centre shortly after 8pm.
He is being held at Clontarf Garda Station under Section 4 of the Criminal Justice Act, and can be held for 24 hours.
Mr Dennehy, a 50-year-old retired Cadbury chocolate company executive, was found dead in his Clontarf apartment on Wednesday afternoon.
A post-mortem examination found that he died from a single stab wound.