I would find it hilarious is the assassin remained at large because people refused to snitch.
Also remember, things are newsworthy because they're novel. US sees like 2 gun deaths per day and thousands due to insurance company malpractice, but this one death dominates newscycles.
This is an I'm spartacus moment. Everybody in america should be doing their utmost to ensure the authorities have an overwhelming amount of information and leads to follow to ensure that the investigation eventually concludes with the result most in the interests of the people.
Just gotta dress like the dude. Any passerby might make the connection and report it, it will be a dead end. That, and city cameras will have a hard time picking out anything from the myriad of false positives.
It ain't false information for a passerby to report something they think is suspicious that isn't. It ain't false information to dress how you like.