[9] Khalimov disappeared in late April 2015[15] He was notably absent from a 6 May meeting of Interior Minister Ramazon Rahimzoda with leading police officers at OMON's headquarters in Dushanbe.

Meanwhile, Tajik media quoted unnamed sources in law enforcement as saying Khalimov left Dushanbe on May 1 along with 10 other men, later being seen at Moscow's Sheremetyevo International Airport, Asia-Plus news agency reported.

[21] Although hundreds of Tajiks had already joined IS by this point, Khalimov's defection was an "unprecedented case" due to his being a successful, high profile officer and part of the establishment[3] rather than the poor, from whom Islamist groups mostly recruit.

According to regional expert Deirdre Tynan, Khalimov's defection was nevertheless symptomatic, as "there is an element of doubt in people within the [Tajik] civil and security services about what is the trajectory of their countries" and increasing support for radical religious ideologies.

[23][10] Tajik security authorities claimed that Khalimov personally led a unit of 200 militants, including 50 Europeans in Syria, and was involved in planning terrorist attacks in Central Asia as well as Europe.

[28][29] On 8 September 2017, Khalimov was allegedly killed during a Russian airstrike near Deir ez-Zor, along with Abu Muhammad al-Shimali, with unconfirmed reports of the attack using Russia's precision BETAB-500 bunker-busting bombs.

[23][32][30] On 3 August 2020, Tajikistan's Minister of Internal Affairs Ramazon Rahimov declared that Tajik IS fighters had revealed that Khalimov as well as his family had been killed in an airstrike in Syria, although he later qualified his statement, arguing that these sources were not necessarily trustworthy.