More than three weeks later, terrorist group Boko Haram has claimed responsibility for the kidnapping of hundreds of Nigerian schoolgirls.

According to the BBC, in this newly released video the leader of the Islamist group says, "I abducted your girls." He threatened to sell them.

In mid-April, gunmen stormed a boarding school, forcing more than 270 girls into trucks before driving away into the dense forest. (Via CCTV)

Although about 50 did manage to escape, the rest, according to unverified reports, were sold into sexual slavery in Chad and Cameroon. (Via NBC)

The mass kidnapping occurred the same day a bomb ripped through a crowded bus station, killing 75 people in Abuja. Boko Haram later took credit for that attack as well. (Via SABC)

For more than a decade, the militant group has terrorized Nigeria in its fight to create an Islamic state. (ViaTVC)

Given Boko Haram's history of attacking schools, the Nigerian government earlier concluded the group was behind the schoolgirls' abduction — but for weeks, the group stayed silent.

Meanwhile, Nigeria has come under heavy criticism for failure to find the missing girls — with activists at home and abroad demanding action. (Via Channels Television)

In a televised address, Nigerian President Goodluck Jonathan said it wouldn't be long before the army found the missing girls but also admitted he had no idea where they were. (Via Euronews)

The U.S. State Department lists Boko Haram as one of the world's most dangerous terrorist organizations and blames it for at least 1,000 deaths in 2013.