Edwin Rolando Padron, 57, was convicted in 2012 of possessing child sexual abuse material, PSP said.
The state Megan's Law website shows Padron's most recent address as 1043 Washington Street in Easton and says he works in or near Allentown and Salisbury Township.
He is 5-foot-10 and 220 pounds with brown eyes and black/gray hair, authorities said.
Anyone with information on Padron's whereabouts is asked to call PSP at 610-871-6595 or submit an anonymous tip through Crimewatch.
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