What happened was a lot worse...last time I couldn't find the reference...get your popcorn out people...the lost has been found:
So the Qarmatians (based in Bahrain) being "rebels" had tried to take Baghdad in 1927 but failed and then in ~930 were found outside of Mecca during hajj saying they wanted to do the pilgrimage, they were let in after they promised safety to the pilgrims in the city but once in they
>The Qarmatis fell upon the pilgrims, who had just performed the circumambulation of the Kaba, and created a bloodbath. Many died clinging to the curtain with which the Kaba was covered every year. The Qarmatis derided the Qur'anic revelation by calling out: "HE is in heaven, and shall his house be on earth?" or they mockingly cited Sura 3:97, where it says about the sanctuary of the Kaba: "Whoever enters it is in safety. .
>As the bodies of slain pilgrims were lying unattended in the streets of Mecca, the Qarmatis looted the treasures of the Kata sanctuary, stripping it of its gold and silver decorations. The sacred Black Stone was removed from a corner of the Kate, put on a camel, and carried off to the Qarmati capital in Bahrain
They then declared the end of times by declaring a young Iranian man as the Mahdi. Abu Tahir's personal doctor who later defected and fled to Baghdad, describes in graphic detail the acts of sacrilege perpetrated by the newly manifested mahdi and his Qarmati followers.
>They cursed all of the previous prophets, including Muhammad, worshipped fire, encouraged "incest and pederasty," burnt and desecrated copies of the Qur'an, and broke the Black Stone and placed its pieces in a LATRINE. As the hostile account of a defector, the doctor's words should be taken with a grain of salt.
The Mahdi had declared the end of Sharia and a new age of an Abrahabic religion(?)
>However, the fact that the Islamic law was indeed abolished by the Persian youth is confirmed by other sources.
If you read the part about what they were doing e.g. fire worship, incest etc... the Mahdi had deviated too much from "Islam" and Abu Tahir deemed him a impostor and had him killed 8 days after the declaration.
Source: Islam in Historical Perspective, 2016 by Alexander Knysh p. 212-215