after all Shinichi's appearing among publish, they should suspect that the guy is still alive or someone are still connecting with Shinichi-relation. Hence, they should fake a super smart (Shinichi's kind of smart) killing scandals that lead organizations and Conan to follow murder after murder, just to realise that Shinichi Kodo is doing all these at the end; which will drive Conan to a super stuffed situation: how to trace the root-killer to clear Shinichi's name or silent or do it a really clever way so that the Black_org will not trace back to Conan (bc surely he know, they are setting these up to bait Shinichi's relation)