They discovered one improvised explosive device in the garage and another in a drawer in Whittam's bedroom.
Tests revealed they were potentially lethal when combined and used with a detonator device.
So... they found some fertiliser in his garage and some Vaseline in his bedroom? Who doesn't have stuff in their house that could be turned into an explosive when mixed together and combined with a detonator?
I could imagine being a teen today with all this bullshit.
