Thieves are breaking into cars as parents pick up their children from Waters Elementary. View Full Caption Flickr/Brian Drew

LINCOLN SQUARE — A nagging voice in her head told Katie Ronan not to leave her purse in her van when she parked her Honda Odyssey outside Waters Elementary during after-school pickup last week.

"I thought, 'Ah, I'll just be two or three minutes,'" Ronan recalled. "I came back and wondered, 'Why is my window open? S---, it's not open.'"

Ronan is one of at least three parents in the past month to have her car broken into when picking up a child at Waters, 4540 N. Campbell Ave.

"I totally think I was watched," she said. "I think they're highly organized."

After smashing in her car window, the thieves made off with Ronan's purse — "a cheapie Target thing" — along with her credit cards and about $25 in cash.

"It's the season for crimes of opportunity," said Ald. Ameya Pawar (47th), who's requested special attention and police patrols around Waters.

Police are urging people to keep their cars clear of valuables — purses, phones, laptops, etc. — no matter the time of day or time of year.

Said a police department source: "If they see anything of value they will break in your car for it."

In areas like Lincoln Square, residents can be carrying hundreds of dollars in their purses or leaving items like golf clubs or iPads in their cars.

"There's a lot of good potential here," said the source. "In this neighborhood, every few cars will have some really nice stuff. People are trustworthy."

Karen Halverson learned that lesson the hard way.

Just before Thanksgiving, she parked on Sunnyside Avenue to pick up her kids at Waters.

Though she could swear she locked her car, she now thinks she may have accidentally hit the "unlock" button instead.

"It's so weird to me that I didn't lock my door because I'm so neurotic about it," she said.

She left her Coach purse on the floor of the passenger side of the car and returned to find it gone — no forcible entry required.

Before she could cancel her credit cards, the thieves charged about $50 at a Mobil gas station.

"If I can fill up my tank on your credit card, I scored," the police source said of the thieves' mentality.

With school about to let out for a two-week holiday break, the source warned people not to let down their guard.

Thieves are well aware parents will be making alternate arrangements for their children, including drop off and pickup at Chicago Park District programs.

"The bad guy's not stupid," said the source.

For their part, Halverson and Ronan both reported having changed their habits since being burglarized.

Ronan is now walking to the school to collect her daughter.

"I just have my keys and my phone. I'm keeping everything on my person," she said.

Halverson is teaming up with other parents to be on the lookout for suspicious behavior or individuals around the school.

Beyond that, "I'm just keeping an empty car and leaving nothing to attract them," she said.

Safety tips for crime prevention can be found on the 47th Ward website.