At least 48 killed and about 80 injured in explosion
A suicide bomber disguised as a student killed at least 48 people and injured about 80 at a boys' school in Potiskum in the northeastern Yobe State on 10 November.
The explosion detonated during assembly at the Government Science Secondary School and most of those killed were students. It took place at around 07.30 in a crowd of about 2,000 students.
Police believe the attack was carried out by Islamist militants Boko Haram, although the group has not claimed responsibility.
Yobe State was recently placed under a state of emergency as a result of the five-year insurgency mainly in the north of the country.
Boko Haram has been responsible for a spate of kidnappings, most notoriously the April abduction of 200 teenage girls in Chibok in the state of Borno, south-east of Potiskum.
Recently the militia group has stepped up its terror campaign, rejecting an alleged ceasefire agreement announced by the Nigerian government. The name Boko Haram translates as "Western education is forbidden" in the local Hausa language, and its militants frequently attack schools, abducting hundreds of students and killing thousands in its fight for an Islamist state.