HOUSTON -- Thieves who shoplift from Houston-area grocery and drug stores have become more organized, and officials with the FBI believe some of them could be part of dangerous gangs or terrorist organizations, KPRC Local 2 reported Wednesday.

Surveillance cameras at a Houston-area Kroger store caught several thieves unloading shelves full of over-the-counter drugs.

Officials believe the thieves are part of groups like the MS-13 gang, who sell the stolen merchandise to fencing operations for a third of the retail price. The fencing operations then sell the good to wholesalers, who turn around and sell the products back to retail stores.

"They operate in teams. Normally they communicate with cell phones. It is a major nationwide criminal organization," Texas Department of Public Safety Sgt. Johnnie Jezierski told KPRC Local 2.

Authorities believe there are more than 1,000 shoplifters who hit stores in Houston each day, and that most of them are illegal immigrants from El Salvador and Honduras.

"Property crime is treated less seriously than violent crimes or crimes against people. And as a result, if caught, they will serve minor jail time," Jezierski said.

In one case, detectives told KPRC Local 2 that thieves walked out of a store with more than $6,000 in over-the-counter drugs.

Similar organized crimes rings in the past have targeted baby formula, cigarettes and clothing.