WOULD KILLING RAPISTS AN CHILD MOLESTERS BE A CRIME?

i mena saying that one would hunt down molesters and rapists an kill them would that be a crime or would it be a service to the communities that harbor these criminals, afterall the justice system cant watch over these guys case in point like the girl in captivity in antioch, california an all these other missing girls who are being killed by repeat offenders huh, wouldnt that constitute by law a clear an present danger act towards the citizens of these united states ??? tell me what u think we as american citizens can do to protect our communities, so i ask would you on a jury put this guy in jail or set him or her free, keep in mind that the prosecutor would not let oyu as juror know about the rapist background in most cases, or states seeing that the prosecutor would have to hide this rapist background because of political stuff, an certainly make the justice system look bad, so how would u judge this guy or gal who are doin society a favor huh.