It was at 15 o'clock on Saturday that the National Bomb Guard was called in. An area was blocked off by the Johan-Olov school in Horndal in Avesta municipality.
Police confirmed in the evening that the bomb guard was in place but were the company of the incident. Only at 22 o'clock did they go out with the information that it was a grenade that caused the action.
Shortly after 22, the grenade must have been secured and transported away from the site to be damaged, reports Lars Hedelin, press spokesman for the Bergslagen police region, in a press release.