What about the calls on his cellphone to well known Islamist militants. What's more, analysis revealed traces of the explosives in several places in the car (which means they'd been moved around and not put directly in the trunk), and in his locker in the airport (presumably in a secure area).
Despite his assertions, the second set of keys of his Peugeot was in the possession of the former car's owner, and not his in-laws.
Sounds like he got a smart lawyer.