Troopers say Tyrone Cook missed a scheduled verification check and is no longer living at his last known address.
The 45-year-old must register as an offender for life, but authorities are unable to locate him.
Cook was convicted of sexually assaulting a person under the age of 13 and corrupting minors back in 2019.
He has ties to Philadelphia, Chester, Pennsylvania and New Castle County, Delaware
If you have any information on Cook's whereabouts, contact state police at 484-840-1000 or anonymously contact the Pennsylvania Crime Stoppers Toll Free at 1-800-4PA-TIPS.