MENDOTA, Calif. — Authorities say in court documents that a teenager charged with murder confessed to killing a 4-year-old boy because the child was going to reveal the teen molested him.

Fresno County prosecutors have charged 14-year-old Raul Castro as an adult. His arraignment hearing was postponed Wednesday.

The affidavit was filed by sheriff’s Detective Sergio Toscano to get an arrest warrant.

It says Castro lured Alex Mercado into a bathroom and molested him. When Alex threatened to tell his mother, Castro said he held him under water in a bathtub until he died then hid the body in a clothes dryer, the affidavit states.

Castro is scheduled to be arraigned Wednesday on charges including murder and sodomy.