On Sunday night, dozens of gunmen with suspected ties to notorious Islamist terror group Boko Haram murdered more than 40 university students as they slept in dormitories at an agricultural college in Yobe, northeastern Nigeria. This is just the latest carnage to grip the county since an executive-order from President Goodluck Jonathan kicked off an offensive in May, aiming to root out the shadowy rebels.

Here’s a quick rundown of who they are and what they stand for.

1. The group was founded by a firebrand cleric called Mohammed Yusuf

Boko Haram is a Sunni terrorist organization that claims links to Al Qaeda and other groups of a similar ideological bent, both in the region and internationally. The group’s current incarnation was founded in 2003 under the leadership of a young Islamic cleric named Mohammed Yusuf. He was killed during a failed uprising against the Abuja government in July 2009 that spread across four northern states, but was successfully crushed by security forces. During the crackdown, Yusuf was arrested and killed while in custody. Since his death, his former deputy Abubakar Shekau has taken Boko Haram’s reins of power and launched a violent campaign largely targeting police stations, federal institutions and Christian villages across northeast Nigeria.

2. They kill students because they hate Western civilization

A rough translation of Boko Haram is: “Western civilization is forbidden.” The group’s main goal is to establish an Islamic caliphate within the country, which would allow for the implementation of sharia law. Boko Haram sees public schools as places where students are brainwashed by a “Western” curriculum, and earmarks them as significant targets in its war to drive secular, federal institutions from Nigeria’s Islamic heartland. 

Read it at Time.