By Tom Mustin

HIGHLANDS RANCH, Colo. (CBS4) – The Douglas County Sheriff’s Office is asking residents to be vigilant after a series of vehicle and home break-ins.

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Deputies say roving gangs of crooks are looking for open cars and garages. The sheriff’s office’s message: “They’re fast, they’re organized and they’re here.”

Flashing signs are warning residents of a crime wave sweeping through Highlands Ranch.

“It makes you very nervous and fearful,” Resident Liesl Grossi told CBS4’s Tom Mustin.

Resident Liesl Grossi speaks with CBS4’s Tom Mustin. (credit: CBS)

In the past few months, opportunistic criminals have descended on Douglas County, stealing from open garages and unlocked cars. Surveillance video shows a stolen car driving into a Castle Pines cul-de-sac.

Three criminals leap out, testing for open car doors. They quickly rifle through two cars, steal what they can then drive off. Grossi says vandals targeted her car outside her Highlands Ranch home.

“It just makes us uneasy knowing there’s [sic] people around looking in the houses and garages and traipsing about the neighborhood and being so brazen as well,” Grossi said.

(credit: CBS)

Home video from a few doors down shows a man get out of a car, check a car door than walk into an open garage. He then leaves and heads to another home as his driver turns off his lights and follows.

“All these neighborhoods out here in Highlands Ranch have security systems and cameras, so obviously they’re feeling like they can get away with it. Hopefully, they can’t and they’ll be caught,” Grossi said.

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Chief Deputy Steve Johnson says the Douglas County Sheriff’s Office is seeing a steady increase in crimes of opportunity. Highlands Ranch has become an easy target.

“It is getting problematic for us. If they know there’s a target rich environment, they’re always going to come back and they’re always going to hit it,” Johnson said.

Johnson says many of the criminals are coming from out of town.

“So they come down here in stolen cars, look for more stolen cars, look for more property to steal.”

(credit: CBS)

The Sheriff’s Office has added extra patrols, including unmarked cars.

They’re hoping that residents will do their part to discourage the thieves. Meanwhile, Liesl says she’s learned her lesson.

“We’re  safe we just need to take an extra step and watch everything- watch the kids and cars and keep everything locked.

The Sheriff’s Office says they’ve made some arrests, but the public needs to do its part as well. They’re advising residents to keep their homes well lit at night.

Also, close garage doors, lock your cars and bring valuable items inside. They’re also asking residents to report any suspicious activity.

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Tom Mustin is CBS4’s Weekend Anchor. He has been with CBS4 since 2002, and is always looking for great story ideas. Connect with Tom on Facebook or follow him on Twitter @TomCBS4.