PALM SPRINGS, Calif. -

A rock the size of a softball broke through the rear passenger window of a car traveling on Highway 111 early Saturday morning.  

"It's really sad to hear that we have to worry about being in our cars and having rocks thrown at us," said Paula Karcher, a concerned local resident.

The driver was a mother from Orange County who had her 13- and 6-year-old daughters sleeping in the car at the time. The rock ended up wedged in the rear seat, just an inch above the head of the 6-year-old child.

"I think people don't think about their actions and a little girl could have innocently gotten really hurt," said Mary Beth Somers, a local resident and mother of two.

Luckily, the only injury was a minor cut to the 6-year-old's foot from broken glass. 

We spoke with Palm Springs Police Sgt. Kyle Stjerne on the phone.  He couldn't provide us with more details but said they're taking this isolated incident very seriously.

He also warned drivers to remain vigilant, especially on roads with high speed limits.

"Watch together as a community and that police are aware of people on the sidelines of the streets," Karcher said. 

Police patrols have increased in the neighborhoods adjacent to Gateway Drive and Highway 111. But valley residents worry that this sort of reckless act can't be prevented.

"I think it's a terrible thing and I don't know how to catch someone like that," said JoAnn Davis, another concerned local resident. 

"People are going do what they're going to do. You just have to be aware of your surroundings and recognize anyone that would do something like that," Somers said.

"Hopefully enough attention is drawn to the fact that this has occurred that another act will not happen," said Palm Desert resident Rainer Bergmann.

Police say this is a very serious matter. If caught the people responsible face felony charges, possibly even assault with a deadly weapon.

If you have any information regarding the case you're urged to contact the Palm Springs Police Department at 760-323-8115.