Final answer:
Custodial interference in the first degree involves knowingly taking or retaining a child or incompetent person without legal right, in efforts to deny the custodian's legal access, constituting a Class C felony under RCW 9A.40.060.
Step-by-step explanation:
Custodial interference in the first degree, as defined by the RCW 9A.40.060 (Revised Code of Washington), occurs when a person, known to have no legal right to do so, takes or retains a child or incompetent person with the intent to deny access to the child's or incompetent person's custodian or legal guardian. Typically, this is a situation where one parent, who does not have legal custody of the child, takes the child away from the custodial parent in violation of a custody order. According to Washington state law, this action constitutes a Class C felony.
To be charged with this offense, the individual must knowingly act without authorization and with the intent to hold the child or incompetent person for a prolonged period or permanently. The underlying intent of such laws is to prevent unlawful disruptions to a legally established custodial relationship. The statute specifically outlines first-degree custodial interference as a serious offense because it involves the taking or retention of a child or incompetent person that could put the victim at substantial risk of illness or significant physical or emotional harm.