Some 20 Russian tourists were hospitalised with severe alcohol poisoning in Bodrum in late May on their return from a sailing tour organised by a local company.
Four of them died in Turkish hospitals, while another victim died later at a Moscow hospital.
The lawyer, who represented the interests of a husband of one of the deceased tourists, said all four Turks were involved in production and distribution of fake alcohol.
He also said that the owner of the yacht and two more organisers of the sailing tour were sentenced each to seven years in prison.
The Turkish Ministry of Agriculture said in an official statement after the incident in 2011 that the methyl alcohol content in the fake whiskey, called Mister Burdon, was three times higher than normal.
According to Turkish officials, a company called Jasmine imported the fake whiskey into Turkey from northern Cyprus. Some 12,000 bottles of the bogus whiskey were sold at local markets.