Mordin has never bothered to keep quiet about the LSR clinic, and it is relatively famous since it's, y'know, totally free if you can't afford it. On top of that, Mordin's relatively famous himself, and while he hasn't done much in Locke City, he's well-known enough that the police might well approach him, and he's spoken out in favor of environmentalist groups before. He's got a pretty distinct speaking style, too - you hear him once delivering a TED talk and you never forget his voice. He's also going to be trying his damnedest to get access to the crime scene to do his own analysis, focusing on mainly his former FBI connections.