The released group included 27 students, teachers and relatives, the state government said in a statement at the time of the abduction.
The gunmen, wearing military uniforms according to witnesses, broke into the Kagara Government High School of Science on February 17. One student who died during the attack was named Benjamin Habila.
Niger State Executive Governor Abubakar Sani Bello has tweeted that state governments have received the released.
This happens when hundreds of schoolgirls were abducted in the early hours of Friday when gunmen stormed a public school in Zamfara state in northwestern Nigeria.
Schoolgirls were taken from their shelters by gunmen who attacked the government girls’ high school in the city of Jangebe, a senior government official with knowledge of the incident told CNN.