MIAMI BEACH, Fla. – A group of former emergency workers, retired cops and concerned Miami Beach residents are warning visitors about the hazards of leaving their valuables unattended.

Miami Beach Crime Prevention & Awareness has a Facebook page that shares information on suspected criminals on Miami Beach. On Sunday, a small group walked the beach to urge sunbathers not to become victims of beach thefts.

"We're with the crime prevention group -- you left your stuff unattended," volunteer David Adams told one beachgoer.

Miami Beach police said beach thefts are a problem here and in any busy coastal community.

Last week, a woman who just moved to South Florida reported her wallet, phone and keys were stolen while she was swimming. In August, someone stole an off-duty Doral police officer's loaded gun while he was swimming at night, when the beach is technically closed to the public.

On Sunday, volunteers saw unattended beach blankets and bags that could have been prime pickings for thieves.

Volunteer John Deutzman said some beach criminals use bicycles to make a quick getaway after stealing.

"So now they have transportation to use the stolen card more," he said.

Most sunbathers on Sunday seemed to appreciate the extra sets of watchful eyes.

"Just getting the word out. They tell one person, they tell another. Pretty soon people are much more careful out here," Adams said.