I can definitely see this happening, depending on how you get that information out there. It actually reminds me of dozen of Forensic Files cases where people/law enforcement told the general public about WHO the killers were or what type of methods they were doing.
You know what happened?
These criminals changed their methods, they went on the run -- making their capture go from months to years, they killed people who were actually still alive -- they did whatever they could to not let someone get the upper hand on them.
So even if you did have a time machine and knew where these guys were and what they did -- it's not a guarantee that knowing the information would save someone, especially if you're the type to just bust through and yell it to the streets.
For me, If I did decide to do a time machine, I'd most definitely go back into moments in time where I held back myself. Those moments of bullying, following peer pressure, being a bit lazy in school -- none of that would happen. Maybe the Butterfly Effect of that would be not having certain friends I had in grade school, but if there's one thing I'd learn, it's that I'd be better off without them. I would be stronger and a bit better.
It begs the question of whether I would've learned the same lessons I did growing up, and it would also beg the question if not having these failures and experiences would make me as empathetic as I am now.
So I think I'd have to do the "Loop Hole" trick -- allow my younger self to have those previous failures before the worse comes, and explain to them that what happens in the future isn't entirely bad...but it could definitely be better if I apply myself more.