Banned terrorist outfit Tehreek-e-Taliban Pakistan on Wednesday confirmed the death of its commander Umar Mansoor, the man who masterminded the 2014 attack on a school in Peshawar, Dawn reported.

“We confirm the death of Khalifa Umar Mansoor,” the outfit’s spokesperson Muhammad Khorasani said in an emailed statement to journalists, adding that Usman Mansoor Hafizullah will take over as the group’s commander in the Pakistani cities of Darra Adam Khel and Peshawar.

Reports of Mansoor’s death had emerged in 2016, as well, but were never confirmed. The Taliban’s statement on Wednesday comes a day after six suspected militants were killed in a US drone strike targeting alleged militant hideouts at the Pakistan-Afghanistan border, PTI reported. It is unclear whether Mansoor was killed in these strikes, or in 2016.

Mansoor is believed to have planned the December 2014 massacre in Peshawar – the deadliest militant attack in Pakistan’s history. Seven Taliban militants had scaled a wall, entered the auditorium of the school where students had gathered for an event and opened fire. Around 122 students and 22 teachers and staff members were killed.

He had also claimed responsibility for the attack at Pakistan’s Bacha Khan University in 2016.