The body of the 24-year-old was found in a shallow grave near Moyross. He had been shot three times, once in the head.
Members of the McCarthy Dundon gang are suspected of carrying out the murder over a drugs debt.
One of the main suspects is a teenage boy known for his extreme violence.
Those arrested yesterday are being held in garda stations in Limerick city and county, Co Clare and Co Tipperary.
Four men and two woman are being held under Section 50 of the Criminal Justice Act, 2007 and another man and woman are being held under Section 31 of the Offences Against the State Act.
More than 100 gardaí under Chief Superintendent David Sheahan and Supt Frank O’Brien took part in the search operation which commenced at 7am.
The searches were concentrated in the north side of the city.
Addressing mourners at Lee Slattery’s funeral Mass in St Munchin’s Church, Canon Donal McNamara, described his murder as “barbaric”.
Five people were arrested on June 10 in connection with the murder.
A gun found during Garda searches has been linked to the murder.