Workplace accident?
“Minneapolis Fire Chief John Fruetel said the explosion was reported at 8:16 a.m. at 516 Cedar Avenue – a building that includes a grocery store, several apartment units upstairs, and is connected to the Islamic Civic Society of America & Masjid Dar Al-Hijrah mosque on the ground floor.”
http://www.myfoxtwincities.com/story/24341053/explosion-fire-cedar-riverside
I asked the local reporters who had the initial story about this 6 months after it happened. Never got any reply.
OJT (on the job training) on bomb making isn’t a good idea.