CHICAGO (CBS) – On Chicago’s South Side, someone’s been targeting mail carriers. As CBS 2’s Kristyn Hartman learned, they’re stealing bundles of mail knowing some of it could have money or checks inside.

We spoke with one of the victim’s co-workers. The fellow postal employee asked for anonymity.

She said, “He was in the hallway, and they went to his truck, and took all his mail, and he tried to tell them it isn’t worth it. We’re all shaken up because it’s been in areas with robberies.”

According to Chicago officers and postal inspectors, over the last two days on Chicago’s South Side, five different carriers reported mail thefts – at least one was at knifepoint.

“Who’s gonna stick up the mailman?” asked Lee Baker.

“Well, why do people rob banks?” countered Mark Reynolds of the U.S. Postal Service. “Because they think that’s where the money is.”

Some envelopes hold checks and cash, especially around the holidays. Still, five cases in one general area?

“It certainly is an alarming number of incidents,” said Reynolds.

It’s why inspectors are on it. They say they have some solid leads, and that the cases might be connected.

They think they’re looking for a man or men who got away in a dark blue or black Pontiac.