JACKSONVILLE, Fla. -

The warning can't come often enough. Thieves are watching women in parking lots, waiting for them to get out and leave their purses hidden in their cars. It doesn't matter if your car is locked or not, they just break the window. And in each of the cases we've followed, the car alarm never went off.

Channel 4 wanted to see how often women were actually leaving their purses in their cars. We brought along our crime and safety expert Ken Jefferson to a fitness center parking lot on the Southside. We watched like the crooks would.

In less than five minutes, we found a woman who left her purse locked in her car as she went to work out. We asked her why she made the decision to leave her purse in her car.

"I suppose just out of ease and convenience," she said. "Just quickly run in, get a workout and get right back in."

She then admitted to us she was inside working out for about an hour and a half. Jefferson showed her just how fast a crook can strike.

"First thing I would have done would be to check the door locks, no one knows what I'm doing.  Then I could take a punch and punch your window out, no alarm is going to go off at this time,  reach in, I see it on the floor, grab it and I can just walk away," Jefferson said. "You know, if I was a thief and I took your credit cards or your debit cards, within 30 minutes, I compromised it.  And if I have your driver's license, I can steal your identity as well."

Just as we finished our interview with this woman, we spotted another woman who says she made the same mistake. We asked our second woman if she would think twice about leaving her purse behind again.

"Absolutely.  Once you hear of an episode in one parking lot where you park your car,  you definitely think twice," she said.

She then told us her reason for not taking it in was convenience and because she got busy with her two kids.

We certainly know moms are busy, but Jefferson reminds her there are other options.

"Either take it with you, lock it in [the locker room], or just bring the essentials," said Jefferson.

"I will, starting tomorrow, for sure," she responded.

A third woman we spotted in this same parking lot, did the exact same thing. She left her purse in her vehicle.

"I just thought it would be safer in the car because I don't need it in the gym," she told us after we asked her why she didn't just take the purse inside.

We interviewed a detective with the St. Johns County Sheriff's Office last week, who has worked dozens of these purse thefts from cars.  He reminds everyone that thieves are not just targeting fitness center parking lots, but they are also targeting day cares, rec. centers and ball fields. 

The detective's advice is to come up with a plan before you leave the house and ask yourself what you are going to do with your purse when you get wherever you are going.

4 Things You Should Never Leave In Your Purse

Many victims of these purse thefts tell us the crooks used their stolen checkbooks, left inside heir purses, to withdraw thousands of dollars from their bank accounts. That begs the question, are we carrying too much in our purses?

According to the same St. Johns County detective, there are four things you should not carry in your purse:

  1. Social Security Card:  It's all a crook needs to assume your identity so memorize it.
  2. Checkbook: If you need to write a check, just take one with you.  In most cases the detective has worked, the crooks used those checks to trick bank tellers into cashing them at the victims' banks.
  3. Passport: Leave your passport at home.
  4. Birth Certificate: You would be surprised how many people have birth certificates in their purses. They are really hard to replace and make it easy for a thief to steal your identity.