"We announce our allegiance to Muslims Khalifa, Ibrahim ibn Ibrahim Awad ibn al-Husseini al-Qurashi," said by the Abubakar Shekau allegedly voice, in the message that has been sent through a Twitter account, with no authenticity confirmed yet. Al-Qurashi, better known as Abu Bakr al-Baghdadi, is the leader of the movement that proclaimed a 'caliphate' in a region covering parts of Syria and Iraq. The Shekau photo does not appear, which differs from most messages sent by Boko Haram, where the Islamist leader is shown often in passport photos.

In the past recent months have been signs of closer links between Nigerian militants and the ISIS, including the use of similar forms of communication with the outside world. Boko Haram began broadcasting videos that resemble those produced by ISIS.

Boko Haram maintains six years ago a violent campaign against the Nigerian state, which has claimed more than 13,000 lives.

Boko Haram ("western education is forbidden"), is an Islamic fundamentalist organization which uses terrorist methods. Officially, Boko Haram claims that they struggle for Sharia, fight against government corruption, prostitution and other vices. According to them, they blame the Christians for these evils, as well Western culture for trying to teach something to women and girls.

The terrorist group is known to have as main victims, young women. Many girls were captured and taken to be raped by warriors. Sometimes, the girls are taken to Muslim villages and released, for the entire Muslim population to rape them, so Boko Haram popularity can grow. Girls are raped until they accept become Muslim and marry one of their tormentors. The girls who refuse, even after about four weeks are released, but before leaving is custom sanding the right nipple of the victim until it disappears.

Since June 2013, the United States officially offer a reward of $7 million, for information leading to the capture of Abubakar Shekau. According to Nigerian government sources, Shekau is dead since 2009. He would have been replaced by an impostor, but there was no confirmation.