On 20 March 2002, Ibn al-Khattab, who led his militia against Russian forces in Chechnya during the First and Second Chechen War, setting up many effective ambushes against Russian forces as well as managing the influx of foreign fighters and money, was killed when a Dagestani messenger hired by the Russian Federal Security Service (FSB) gave Khattab a poisoned letter. Chechen sources said that the letter was coated with "a fast-acting nerve agent, possibly sarin or a derivative".