CHICAGO (CBS) – For weeks, there were constant ripoffs from mailboxes in the West Loop.

Residents just couldn’t figure out how thieves were getting in.

Now, a woman is behind bars, facing federal charges. Thanks to a traffic stop by Chicago police, CBS 2’s Jermont Terry reports.

For those living in the West Loop the arrest is a great start. However, the looming question: who else was in on this crime spree.

It’s not that simple for people in this neighborhood to get mail, especially with thieves gaining access to secure buildings by using a U.S. postal worker master key.

Neighbors were forced to install a digital key pad, mainly because crooks kept stealing mail, using the key postal workers should only carry. But clearly these were no mail carriers.

“It was such a violation to have someone pry open the mailbox,” one woman said. “It’s ridiculous.”

These thieves walked away with personal information, too.

“Our neighbor had her identity stolen,” a resident said. “These people had taken out credit cards and mortgages.”

CPD arrested Aliyah Massari. More at CBS Chicago