CHICAGO (CBS) — Several young men are believed to be behind a crime wave: a series of recent sexual assaults and armed robberies in Chicago’s North Park and Edgebrook neighborhoods.

They happened within blocks of each other, starting on Aug. 26 and at about the same time between 9:30 p.m. and 10:30 p.m.

READ MORE: Breast Cancer Survivor Urges Women To Talk To Doctors About Their Imaging, After Her Mammogram Didn't Go Far Enough

CBS2’s Charlie De Mar reports, the neighborhoods are shaken up after the attacks.

But a stolen Ventra CTA card taken from one of the victims may be a big piece in solving the case.

Police released, last week, photos of two of the men they say are responsible for at least three of the recent armed robberies in the two neighborhoods.

“On high alert, especially since it was right in front of our home,” Edgebrook resident Jamee Delroy says.

Police say a group of three to five men approached a woman with a gun, hit her with their fists, robbed her, then the victim was allegedly sexually groped over her clothes.

READ MORE: Supply Chain Issues: 'There Really Are Problems Everywhere,' Even For Small Companies

Asked why her neighborhood, Delroy said, “You sometimes you know because cops live here or this is an area where a lot of fireman and policeman live..maybe they think it’s not as patrolled as much.”

The story was the same on the 3400 block of West Carmen in North Park on Aug. 29. And just three days earlier, another robbery in the 5700 block of North Kimball.

“It came through on my Twitter feed, the pictures of them at the train station,” said Lorrie Yurick, who works near where the North Park attack happened.

Those surveillance photos were captured at a CTA stop, where the robberies used one of the victim’s Ventra cards to board.

“I think it’s random,  drove down the street  saw someone to attack or someone who wasn’t’ paying attention and that happens,” Delroy said.

MORE NEWS: Man Attacked, Robbed At Gunpoint Near Wicker Park

Both aldermen from the 16th and 17th Wards will be meeting with Police Superintendent Eddie Johnson Wednesday to discuss the incidents and patrols in the area.

Charlie De Mar