HOUSTON -

Houston-area fast food restaurants are open late, operate mostly in cash and are often staffed by crews of young adults or minors.

A security expert told Local 2 that's what makes these establishments attractive targets for robbers.

"They're actually looking for something easy in and easy out. That, in my opinion, is the rationale behind it," said Hanan Yadin of Houston's ISI training center.

From Sugar Land to northwest Harris County to southeast Houston, there have been a rash of fast food robberies. Of the eight we identified since July 23 four of these violent crimes took place in the last 48 hours, including two this Thursday morning.

While most fast food chains are outfitted with state of the art surveillance systems, alarms, fortified drive-thrus and adequate lighting, Yadin says these safeguards don't always deter criminals, because in a lot of these cases they're under the influence of drugs or alcohol so they're not thinking rationally or clearly.

Yadin says by shooting and hurting just one person, their intent is clear.

"The message is, 'We're serious, don't mess with us'," Yadin said.

Yadin is an expert in tactical training and says if you are unarmed, you should always stay calm and obey all commands in an armed robbery situation.

Many fast food chains put employees through rigorous security training.