Deaths caused by cheap homemade spirits are not uncommon in Russia, which has been plagued by high alcoholism for years, although they have decreased compared to the record levels of the 1990s.
Six of the September deaths occurred between September 10 and 17 in the Leningrad region.
"Forensic examination of the bodies of six deceased persons revealed high or fatal levels of methanol," the Russian investigators stated.
Three people have been arrested suspected of involvement in the alcohol-related deaths.
Earlier in the week, prosecutors sentenced two people to nearly ten years in prison for manufacturing and selling a counterfeit cider drink that killed 50 people in 2023.
Despite tightened legislation after similar incidents, cheap homemade spirits with methanol are still available in Russia, especially in rural areas where many are poor and the price of vodka is prohibitively high.