Greek Premier Alexis Tsipras, currently in New York for the UN General Assembly, learned on Friday about the death of his brother-in-law at an Athens hospital.
58 year-old Grigoris Karagounis was married to Zanette, the sister of the prime minister. The couple had two children.
Karagounis died at the Evgenidio Hospital. Tsipras had visited him last Sunday before he flew to New York.