CENTENNIAL, Colo. -- Investigators call them "Smash-and-Grabs."

That's where a thief shatters a window, crawls inside a store then makes off with some quick cash or other loot.

It's happened 19 times this week in the south metro suburbs.

Aurora police told 7NEWS that nine businesses were struck late Sunday or early Monday.

The thief or thieves struck again early Wednesday smashing windows at seven businesses in Centennial, one in Foxfield and three in Greenwood Village.

"It looks like they just went for some quick cash," said Chief Bruce Williamson, of the Arapahoe County Sheriff's Office.

Don Johnson manages Salon du Soleil near East Arapahoe Road and South Quebec Street.

"I got a call from the alarm company around 2:15 this morning after the motion detector activated the alarm," Johnson said.

"I think they were just looking for cash," Johnson added. "They didn't take the computer, the screen, any products or any of the stylist’s tools."

From there, the thief or thieves proceeded east on Arapahoe Road hitting several other hair, nail and tanning salons and two dry cleaners.

Tami Harris, owner of Snappy Nails, told 7NEWS, "I think people are just getting crazy. I mean they go in, break the window, then make a big mess and leave."

Because many of the salons are owned or operated by Asian-Americans, 7NEWS asked Chief Williamson if any of the businesses were targeted because of a bias against that group.

"We don't have any information about that at all," Williamson said.

The chief also said there's no reason to think that the break-ins are part of a gang initiation or a plot to extort protection money.

"Why? Why salons?" Kristi Alexander asked Wednesday evening. Alexander, who owns a hair salon very near Salon du Soleil, said the smash and grabs were perplexing given the fact such a small percentage of customers actually pay with cash. Salons like hers have very little cash on hand, she said.

"It makes us all aware of our surroundings," Alexander added.

One business owner, who did not want to go on camera, said she was worried about gangs. But neighboring business owners said the crimes were likely just crimes of opportunity.

"This is really a dark area at night," said Charles Grandy, manager of the United Studios of Self Defense.

Grandy, who used to work in security, said business owners should consider putting in more lights and installing security cameras.

"They should have proper signs posted," Grandy added. "Signs warning that 'you're on camera.'"

He said hidden cameras don't deter break-ins.

Investigators in Aurora, Greenwood Village and Arapahoe County are working with business owners to determine whether any of the break-ins were caught on camera.

"Unless there is a witness, or something recorded on tape these types of crimes are very difficult to solve," Williamson said.

7NEWS reporter Lane Lyon contributed to this report.