GREENWICH, CONN. (CBSNewYork) – A shocking theft has taken place at a suburban church, and police are looking for a thief who poses as one of the faithful.

He walked into 9:00 Mass on Sunday, not for worship but for loot. Saint Catherine of Siena Church in Greenwich was robbed by a man who knelt, appeared to pray, took communion and even chatted up church members before he struck.

“I couldn’t imagine being there and assuming that someone next to me is going to be stealing from me or stealing from my church,” Greenwich resident Aaron Boxer told CBS 2’s Lou Young. “That would be a real breach of trust right there.”

A lot of the witnesses told police that they felt as if the thief was conning them. He had a hard-luck story about needing money to fix his car. They told him to wait for the priest, but when no one was looking he walked into the sacristy at the rear of the church, taking advantage, apparently, of the confusion between the 9 a.m. and 10 a.m. Masses.

“He came in nonchalant — like he knew what he was doing — and made his way over to the safe,” parishioner Barbara Glynn said. “They weren’t paying too much attention. They thought he was supposed to be there to do something, and the next thing they knew he was gone, and so was the collection bag.”

Cops think that the man may have done this before.

CBS 2 has been told that at least one other church in the area was approached in a similar manner this past Sunday.

“Some of the parishioners were very observant and were able to give us a lot of clues,” Lt. Kraig Gray of the Greenwich Police Department said. “And we have a solid suspect that we’re going to follow up on.”

Police believe that this incident could be part of an emerging pattern that could extend well beyond Fairfield County.

Because the mass collections had just been taken, the church does not have the exact amount of how much was stolen. But the police is hopeful that they’ll be able to recover at least some of the cash.

There aren’t many things one can do that are lower than stealing a collection bag from a church. Share your thoughts and comments on this disturbing story below…