MOSCOW (AP) — Doku Umarov, a Chechen warlord who had threatened to attack the Sochi Olympics and claimed responsibility for some of Russia’s deadliest terror attacks in recent years, was reported dead on Tuesday by the Islamic militant group he led. One of Russia’s most wanted men, he was 49.

Umarov’s death has been claimed repeatedly in the past, but this appeared to be the first time such a report has come from the organization he headed.