I would like to think such horrors would be a lot harder to pull off now, but there are potent lessons behind how creeps like Harvey and Swango got away with it.
Serial killers were protected for ages because too many law-enforcement people thought they were a myth. Likewise, people just did not realize that lower-level staff in hospitals had lots of opportunities to off the patients. And if yer cold-blooded enough, you pick the right old and sick and it didn’t seem suspicious back in the day. Now I think anybody who had unusual numbers of patents dying would be investigated pronto. Normal folks aren’t used to psychopath tricks — if this guy were up to something he wouldn’t joke about it, would he? Both Harvey and Swango did this to blunt attention. And there’s an additional lesson with Swango: more than once, when suspicions arose about him, the hospital cared more about its reputation than the patients, and simply let the murderer go or transferred him.