The group Anonymous is hacking for a good cause. Anonymous, which is known for shutting down governments and big businesses’ websites, will be shutting down the terrorists’ websites instead.

The Telegraph reported that Anonymous in Belgian uploaded a video to Youtube, warning “al-Qaeda, the Islamic State, and other terrorist” that they are next on their list.

The warning is a response to the killing of 12 people at the Charlie Hebdo offices. Cherif Kouachi and Said Kouachi went on a killing spree at the Charlie Hebdo offices because the two did not like the magazine’s satirical depiction of the Islamic prophet Mohammad.

Cherif Kouachi reportedly told witnesses that the killing was to “avenged the Prophet Muhammad!” Cherif Kouachi and Said Kouachi were killed in a gunfight with French police officers on Friday.

The person in the Anonymous video is dressed in the group’s traditional all black garment and has a “Guy Fawkes mask” covering his face.

The Telegraph quotes the individual as saying, “We are declaring war against you, the terrorists…freedom of expression has suffered in human assault…and it is our duty to react.”