[DanBC]

> What you refer to as a complication was him testing positive for explosives or poison.

You might want to look at the Birmingham Six.

They were from Northern Ireland (and thus automatically suspected of terrorism) and living in Birmingham; they were travelling to attend the funeral of a childhood friend (and he was a terrorist); they travelled on the day a bomb went off in Birmingham; and they played a game of cards on the train.

Those cards were coated with nitrocellulose.

The fragments of nitrocellulose on their hands tested positive as nitroglycerine, and that bit of "evidence" was used to convict them of a crime they did not commit and imprison them for very many years.

http://www.bbc.co.uk/news/uk-england-12664938

You shouldn't make assumptions.