If they have little to go on except something superficial like articles of clothing, they will still put out the info they have.
Here’s the deal: people can discard clothing, but they can’t go back and undo the fact that they were wearing it the day of the crime. Some member of the public might have seen something or known some piece of information that might line up with that clothing description of the perp. They call in a tip, such as, I saw a guy who’s known around da hood wearing something like that on that day.
Anything, any little thing might give them a starting point.
Also, maybe they can get some kind of ID from the caps. It’s good to remember everything one can from something like this. Where is the harm?