During an open house, sellers typically secure valuables like jewelry, electronics and personal information, but locking up medicine cabinets may be next on the list.

Thieves posing as potential home buyers have targeted prescription drugs while attending open houses in San Diego, according to a local realtors' group - and the federal Drug Enforcement Administration confirms drugs appear to be entering the black market in that way.

"A lot of times the realtor is alone in the house and the bad guys will go in pairs," said Kevin Burke, who is on the board of directors of the Greater San Diego Association of Realtors. "One will engage with the agent as the other goes through the house."

The bandits will then make their way into the master bedroom bathrooms, getting into the medicine cabinets, said Burke.

"Stealing drugs from open houses is indeed a technique drug thieves use to obtain controlled substance prescription drugs," said Barbara Carreno of the Drug Enforcement Administration.

Opioid painkillers, ADHD drugs, anti-anxiety drugs and muscle relaxants such as Xanax and Valium are among those stolen during these kinds of thefts, said Carreno.

The DEA has enforcement groups called "tactical diversion squads" (TDS) that include special agents, diversion investigators, intelligence analysts, and state and local task force officers who work to investigate prescription drug trafficking.

Carreno said the open house thefts of prescription drugs have been found by the TDS on the black market.

Realtors in San Diego are warning homeowners looking to sell homes about such thefts, encouraging them to be cautious and avoid becoming a target.

"The take away here is common sense," said Anthony Manolatos of the Greater San Diego Association of Realtors. "When an agent is showing your home and you're not there, take your valuables with you or lock them in a safe."