Could the attacks have been stopped?

Powerline finds the tale of a man caught running weapons in Germany.
Not just any gun runner.
They discovered that the vehicle had been professionally modified to create secret compartments for weapons. The cache reportedly included eight AK-47s, two pistols, two hand grenades, fuses, detonators and a half pound of TNT. The man had driven from Montenegro through Croatia, Slovenia and Austria before being stopped in Germany. The GPS in his car was set for Paris.
If you want gun control, here's someone to look out for.
Not the ordinary citizen who wants to protect themselves.