Do parents have the right to NOT turn in a sexual offender?

Proposed scenario: An 8 yr old child is acting out sexually but says no one is abusing her when queried by the parents. Finally, they find out she was sexually molested by the neighbor, who is a long-time friend of the family, but who is also mentally ill and on permanent disability. Upon consulting with the grandparents, they all agree the best thing is to tell the offender (after verifying he actually molested her) he will be turned in to the authorities if he ever comes near the girl again. Because of these reasons they all agree it is in everyone's best interest that he is not turned in to the authorities unless he makes a move: 1) The man is mentally ill and wouldn't do well or possibly even survive prison, 2) The family plans on moving away asap to keep their daughter away from the molester, 3) Due to religious reasons they believe that forgiveness and compassion overrule prosecution of the man, 4) The daughter has a learning disability and cognitive problems and would not do well in an interview, nor on the stand in trial, 5) The mother of the girl was kidnapped and raped at age 13 and the interrogation by the investigator, and the medical exam, etc. after the rapist was caught (the same day) was worse than the original rape crime (to her) and she did not want to subject her daughter to that same kind of embarrassment and humiliation like she had to go through. With all of these circumstances, does the family have the right to NOT turn in the offender?