EASTPOINTE, Mich. -

They're called gypsies and when the weather warms up, they strike. Typically, they're in and out of a neighborhood in a matter of days, leaving with hundreds, maybe thousands of dollars.

Many of the victims, however, don't know they're hit until it's too late.

Police say the scam typically starts with a knock at your door. While most people wouldn't answer, what if the person knocking said they were from a utility company, or perhaps letting you know about damage just caused to your property?

"They target seniors because they are gullible," said former Eastpointe Police Chief Mike Lauretti.

Most crooks say it's pretty easy to tell which homes seniors live in. You may recall when the Defenders talked to a con man.

"I pat them on the shoulder, make them friendly, trustable," said the man.

The man is a gypsy who told Local 4 Defenders the ins and outs of the "springtime scam."

"I got my ID in my truck, and my truck is parked over there," he said.

Our gypsy says the homes with the lawn chairs on the front porch, metal garage cans, well-manicured flower garden, air conditioners in the window are typical signs a senior lives there.

"They basically work Monday through Friday, 9 to 4," the man said.

Lauretti said he knows the scam well.

"They never work the area where they live," said Lauretti.

As gypsies targeted Eastpointe in the past, Lauretti says "They come out to the house and pose as contractors, whether they are electric company, utility company, cable, roofers, house painters, tree trimmers."

Lauretti says for the typical homeowner, it may be hard to tell the guy knocking on your door is a scam artist.

"They will wear general worker type uniforms, they will have a utility van with ladders on them, maybe a magnetic sign," said Lauretti.

Typically, they tell you they are doing work that could affect your yard, trimming trees, or working on power lines.

"We had a power line fall down on your roof," Lauretti gives an example.

Our undercover con man showed Defenders during a test how easy it was. He was able to get a senior out of his home, and that's the goal.

"Their partner is in the front, and you've just left your front door wide open, and they'll go in the house and steal you blind."

The crook who is going through your home, looking for your valuables, doesn't mess up the place. They want to take your cash or jewelry and get out.

Typically, they won't leave a sign they were there, so days or weeks may pass before you notice you were robbed.

Another common ploy is the driveway scam. Crooks will tell you they are in the area already working on a project and have some extra material so you could save some money if you wanted work done.

"They will use such a horrible material, maybe mixed with water, while you can't tell while it is drying, they get paid and out the door you go, and by the time you realize it's an inferior product, they are long gone."

Lauretti says the best bet is to go with companies you know. Don't use door-to-door contractors and if you do happen to go outside, always lock your door behind you.

Police also say if you notice something suspicious, call police and make sure to write down plates so your neighbors won't be the next victim.