Nine vehicles were seized and seven properties searched this morning as part of the investigation into the murder of Mikolaj Wilk.
A masked gang of four men burst into Mr Wilk's home at around 3am on Sunday morning, June 10, and attacked him with machetes.
His wife Elzbieta was seriously injured in the incident. Another woman who was staying in the house managed to flee. The couple's two young children were also uninjured.
Mikolaj died two hours later in hospital. A car was found burnt out in Waterfall sometime after the callous killing.
A garda spokesman said investigators are hoping this morning's operation will help direct them to the killers.
Six houses and one commercial premises were swooped on this morning in Ballincollig and the greater Cork area.
During the operation, nine vehicles were seized and are being technically examined. Some of the addresses have been sealed off and are being forensically examined for clues.