PHILADELPHIA (CBS) — Philadelphia Police Officer Denny Clair says he and his partner, both Catholics, lit a candle, went to Mass, and donated to the “poor box,” hoping that as they hid inside Our Lady of Calvary Church, they would surprise and catch a “serial burglary suspect” who had slipped in and looted the church’s donation boxes twice in recent weeks.

After a first long night, huddling inside the empty church during a fierce windstorm, on Thursday night, they were successful.

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Officer Clare and his supervisor, Sgt. John Venit, explained that they heard a clicking at the door and, suddenly, there was the suspect, 28-year-old William Sides.

“He was surprised, you could see the look on his face, it was like, ‘awww’,” Officer Clair said.

Sides, who then tried to run away, was tackled by the officers outside.

“He got a big surprise, I’m happy,” church facilities manager Joe Olivieri told CBS 3. Olivieri had worked with police to set the trap, mounting a security camera, that allegedly shows the break-in.

“It’s gratifying. It makes the job worth it,” Officer Clair reflected.

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Father John Babowitch, the church’s pastor, told Eyewitness News,”it’s a great relief to me and the parishioners.”

Sadly, he added, the suspect, who allegedly had a hypodermic needle in his pocket, instead of breaking in, needed only to have knocked on the door of the rectory next door, where not only money, but kindness and mercy were waiting.

“All he had to do was ask,”Father Babowitch said.

Court records show the suspect had a history of at least five burglary arrests and is awaiting trial on a drug possession charge.

Sources say Sides is also being questioned about burglaries and thefts at another Northeast parish. Investigators say they believe Sides somehow obtained a key to enter the church.

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Police say, when asked about it, he claimed he found it in the church parking lot.