Arbi Alautdinovich Barayev (Chechen: Арби Алаутдинович Бараев) (Russian: Бараев, Арби Алаутдинович), nicknamed "The Terminator", was a renegade Chechen warlord often accused of clandestine links with the Russian special services. In 1996 he became the founder and first leader of the Special Purpose Islamic Regiment, which was regarded as one of the main hostage-taking, kidnapping, and oil-smuggling groups operating in Chechnya during the lawless interwar period that followed the 1994–1996 conflict with Russia.

Barayev's actions contributed significantly to the rise of the Chechen criminal state in the late 1990s, helping to drive out foreign journalists and humanitarian workers while undermining the presidency of Aslan Maskhadov. He reportedly boasted of personally killing over 160 people and is said to be responsible for the deaths of over 50 people from his home village of Alkhan-Kala, including family members. Arbi was an uncle of Movsar Barayev, a key figure in the 2002 Moscow theater hostage crisis.

Movsar Buharovich Barayev (Russian: Мовсар Бухарович Бараев) (October 26, 1979 - October 26, 2002), earlier known as Suleimanov, was a Chechen and militia leader during the Second Chechen War, who led the seizure of a Moscow theater that led to the deaths of over 170 people.

Movsar Barayev, born 1979, was the nephew of the notorious Chechen warlord Arbi Barayev who allegedly worked under FSB guidance. After his uncle's death in June 2001 until his own, Movsar was the leader of a Chechen terrorist militia known as the Special Purpose Islamic Brigade (SPIR). Barayev junior was said to be a sworn enemy of the Chechen leader and elected president, Aslan Maskhadov. He used the nom-de-guerre of "Yassir".

He was incorrectly reported by the command of the Russian forces in Chechnya to have been killed on August 21, 2001, and again on October 12, 2002, eleven days prior to the Moscow theater crisis (this report of Barayev's death came from Colonel Boris Podoprigora, deputy commander of Russia's Joint Group Forces). It was also claimed that two months before the hostage-taking, the Russian GRU military intelligence had arrested Barayev and contained him "until his release had provided leads to the hostage taking at the Dubrovka theatre".