Just like the Gilgo Beach serial murders here on Long Island. Ten years ago several people already gave solid leads to Suffolk County PD that it was Rex Heuermann. Several women including one that Heuermann had taken on a date and who had fled in terror after he expressed an 'orgasmic thrill' while describing the killings in detail, along with a pimp that described how both of the women in his prostitution ring who had disappeared had last been with Heuermann. But those leads were simply shelved and the killer was able to strike at least half a dozen more times until his capture this current year.
There is NO other way to stop crimes cold on sight than having a completely armed citizenry, or at least a population where the density of armed citizens is high enough that criminals FEAR committing a violent act knowing that their probability of being engaged and shot dead by their victim or a bystander is at least in the 80% range.
However, when people collectively do not want to to take charge of their own destiny, most importantly, their ability to counter violence with instant lethal-capable force of their own, you get vastly unarmed populations and a field of dry overgrowth just waiting for a spark to ignite it. In countries like South Korea, all of the serial killers that had graced their history had body counts in the appalling two and even three digit numbers, because of a completely complacent population whose mentality is "wait for the professionals to take care of it". I posted a while ago here about a westerner who fell mortally ill at a crowded train station in Seoul and the throngs of passengers moving past SAW that he was in serious distress and was dying, and not one person called for help. The man ended up being dead, cold for hours in that crowded station before somebody even took notice.