The inmate previously was employed at the mosque as a sanitation worker, police said.
An inmate on work-release is accused of stealing $3,000 to $4,000 from the Easton Phillipsburg Muslim Association.
Charged is Jason A. Burger, 33, who didn't have a permanent address prior to being jailed.
Easton officers on Feb. 8 were called to the Easton Phillipsburg Muslim Association, 1017 Lehigh St., for a burglary report.
Stolen were electronics, supplies and thousands in cash, court records indicate.
Investigators reviewed video surveillance footage, which allegedly showed Burger stealing items on Feb. 2, Feb. 8, Feb. 13 and March 27. The building was closed at the time of the thefts, police said.
Police said Burger previously worked for the nonprofit organization as a sanitation worker, but court records didn't indicate a timeframe for his employment.
The thief appeared to be wear a light sweatshirt with a dark hood in some footage, and in others had a backpack with reflective material on the lower right side. Investigators said they nabbed Burger by distinctive tattoos on the back of his right hand and inside of his right wrist that matched the man in the video.
Burger was incarcerated for a separate crime at the time of the thefts and was employed in the work-release program, effective Feb. 1, according to court records. Burger had been held at the Northampton County Corrections work-release facility in West Easton.
Records showed Burger was not in prison during the times and dates the thefts occurred.
Investigators with a search warrant later raided the treatment facility and seized the backpack used in the crime. Burger allegedly admitted to the burglaries in an interview with police.
Burger is charged with four counts each of burglary, criminal trespass and theft. He was arraigned Monday before District Judge Richard Yetter III, who set bail at $30,000. In lieu of bail, Burger remains in prison.
Pamela Sroka-Holzmann may be reached at pholzmann@lehighvalleylive.com. Follow her on Twitter @pamholzmann. Find lehighvalleylive.com on Facebook.