CHICAGO (CBS) — For the third time in the little more than a week, someone riding a bike was robbed in the South Loop.

Police said a 14-year-old girl and a 33-year-old woman were riding bikes at 16th and Indiana around 8:40 p.m. Monday, when someone in a Buick LaCrosse pulled up and grabbed the teen’s purse.

The girl fell off her bike, and scraped her arm. The LaCrosse fled the scene south on Indiana Avenue.

The attack came on the heels of two similar robberies in the area.

On June 6, a 32-year-old woman was riding her bike near 14th and Wabash, when a black SUV pulled alongside her, and someone inside grabbed her backpack. The woman struggled and was able to wrestle her backpack away from the would-be robber, and suffered only minor injuries.

Two days earlier, a woman was riding a bike near 21st and Calumet, when a car stopped in front of her, a man got out, hit her in the face, and stole her purse. She was treated at the scene.

Many South Loop residents believe a serial robbery ring is responsible, and that has many women on edge.

“I think it’s horrible to have to worry about that,” Lisa Gonzalez said. “I just think people always have to be on the lookout for their safety, and especially as a biker.”

Daureen Collodel said the robberies are representative of “a lot of crime” in the South Loop.

“It’s terrible, and we live in a beautiful area,” she said.

No one was in custody in any of the robberies as of Tuesday morning.

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