In
Cigars, half of the plot is about the Thom(p)sons trying to arrest Tintin, because they think he smuggled drugs on board the boat.
They also rule out Tintin in
King Ottokar's Sceptre, but that's mostly because Tintin was already at the scene of the robbery with the king.
RicardoOlcese:
It seems that the Detectives grew to trust Tintin more as the adventures went by
I suppose that the feeling of trust came after the Thom(p)sons tried arresting Tintin for so many times, that in the end since Tintin always ended up as the mytsery-solver they thought that arresting him was the wrong idea?