Westminster Police Department investigators said they have received reports of at least five houses that were burglarized while the families were gone during fumigation.
"The burglars are ransacking the entire house and taking everything from cash to jewelry to electronics," said Cpl. Van Woodson of the WPD.
Investigators said they believe the houses are burglarized during the ventilation stage of fumigation when windows are open and fans are blowing out poisonous fumes from inside.
"The burglars are breaking into the house and they know they can do it in secret," Woodson said. "They can get up underneath the fumigation tents and get into the houses and have a little more time to do their work."
Police are looking into the possibility that the thieves may be connected with the pest control companies being hired.
"We're looking into it. We have not seen any sort of pattern regarding any particular pest control companies and no pattern regarding the part of town," Woodson said.
The most recent burglary victims said the family was fortunate to have removed their valuables from the home before fumigation.
Other residents have taken precautions in the past.
"I rented an RV and parked it in my driveway just so I could watch my property because there's no guarantee that anybody could enter just by lifting up the tent," said Westminster resident Steve Loya.
Police say they hope neighbors will get involved and report any suspicious activity.
"We want to encourage our residents to care about each other, to watch out for each other and at least exchange phone numbers with people who live around them," Woodson said.