Just found this out after going down a rabbit hole on Wikipedia. According to Deadline, he passed away September 29 after a long illness. 'Til all are one. Ravil Isyanov Dead: ‘NCIS: Los Angeles’ & ‘Defiance’ Actor Was 59 – Deadline EDIT: According to People, he passed away after a prolonged battle with cancer. NCIS: Los Angeles Actor Ravil Isyanov Dead at 59 After Cancer Battle: 'He Was a True Gentleman'