Dexter comes to mind...
I haven’t seen the show, but just know that he is a serial killer. Does he kill pedophiles?
The trouble is that he murdered because he was compelled to, and had a personal stake in murder. It had to be tortuous.
In this case, however, “you want it to look like an accident”, which can be much more peaceful, such as giving them an opioid analag overdose. Because around 50,000 or so Americans are now dying each year because of this, and medical examiners are overwhelmed, it is unlikely they will spend too much time discovering if a sex offender was killed instead of died by accident or his own hand.