Apparently its advanced tools and this poor guy was also taking German classes. The police made quite a jump of conclusions with just that. Now he is considered part of a group training for something big.
Poor guy, even if you bow down to all the crazy rules and demands of public behavior you can still be penalised for "being suspicious". 
Living in a third world country, we need to realise how secure we are in so many aspects and we need to stop taking that for granted.