“If they were bombs meant to produce shrapnel and there had been a lot of people in the area it could have killed tens to hundreds of people, and injuring many as well,” said säger Bo Janzon, who has spent 39 years with the Swedish Defence Research Agency (Totalförsvarets forskningsinstitut – FOI).
According to Janzon, the fact that so many windows around the blast sites remained intact indicates the explosive devices didn’t detonate properly.
“Fortunately, it seems to have been quite a failure. Windows are very brittle and should have broken directly. Most likely, only a part of the explosive device went off,” he said.
“A terrorist bomb of this type can contain between five and ten kilogrammes of explosive material. That he had nails with him indicates that his aim was to main and kill. This can give people very unpleasant injuries.”
Judging from images of the car bomb, which injured two people, the liquefied petroleum gas canisters weren’t especially large.
“The effects weren’t that big, it mostly puffed a little bit. I don’t think it could have done much damage,” added Janzon.