Officials in La Cañada Flintridge began noticing thieves were using Wi-Fi blocking devices to bypass home security systems like cameras and door sensors.

In response to an increase in home break-ins by "sophisticated criminals" in the San Gabriel Valley, the city of La Cañada Flintridge announced Tuesday that it has increased law enforcement patrols and begun taking steps to curb crimes that rely on new technology.

Arabo Parseghian of the city's administrative services department said the city is working with the Crescenta Valley Police Department and Los Angeles County to expand police presence while officials try to stop thieves who are taking advantage of wireless technology.

"For wireless cameras, alarm systems and door sensors, a lot of criminals are now trying to rely on Wi-Fi jammers to combat them," Parseghian said.

He said city officials began noticing criminals were using Wi-Fi jammers to get around them. Blocking devices to bypass security systems so that even if a burglary occurs, they won't alert homeowners.

An attempted burglary a few months ago confirmed officers' suspicions when deputies found items left behind by the criminals, Parsekin said.

"They left some equipment behind, one of which was a Wi-Fi signal blocker which we seized as part of the evidence in the burglary, and we're seeing this as a trend among criminals today."

He added that the city has seen seven to eight burglaries a month lately.

In addition to the increased patrols, the sheriff's department will do some undercover work, and the city will also purchase Flock Safety cameras, which can read license plates and flag suspicious vehicles, including those that may have warrants.

City officials also recommend that homeowners update the firmware on all firewalls and home security devices and install glass detectors on doors that can send alerts.

With the summer holidays approaching, authorities are encouraging residents to sign up for "vacation checks" with the sheriff's department and to communicate plans with trusted people.

"If you trust your neighbors, if you have a good relationship, let them know, ‘Hey, I'm going out of town.' "