A white-bearded terrorist famous for his role in ISIS execution videos was captured in Mosul last week, according to Iraqi media reports.

The man, known as Abu Omar, supervised the executions. He was arrested after informers led Iraqi security personnel to the place where he had been hiding.

Abu Omar was a prominent figure in a number of morbid ISIS execution videos, in which his victims were thrown off of buildings or they were decapitated, while others were stoned to death for offenses such as desecrating Allah's name.

In one of the videos Abu Omar appears reading a list of charges against three people before their heads were cut off. In another, he inspects a pile of stones before a public stoning.

ISIS forces captured large parts of Iraq in 2014, but were gradually rolled back by Iraqi forces supported by a US-led coalition.

An Associated Press investigation found that ISIS left behind at least 133 mass graves, containing between 11,000 and 13,000 bodies.