That is, "unidentified men." Up till now, the Taliban -- or miscreants -- have been directing their violence against girls' schools. Perhaps this latest attack is meant to deflect the accusation that they discriminate based on gender, for PR purposes? "Equal opportunity explosions"?
"Boys’ school blown up in Bajaur," from the Daily Times, April 21:
KHAR: Unidentified men blew up a boys’ primary school in the Zirgiray area of Nawagai tehsil in Bajaur Agency on Monday. The number of schools damaged in this way has reached 38, but it was the first such incident after the peace deal in Bajaur.
That's because there never is real "peace" with jihadis; just lies to buy more time to resume the jihad.