A burglar almost made his way into a home in Florham Park by temporarily shutting down the homeowner's surveillance cameras.

Police say they believe the suspect used a Wi-Fi jammer to knock out both the cameras and the homeowner’s cellphone service.

Home surveillance cameras posted on front and rear doors or perhaps above a garage have become commonplace for those wanting to know who is on their property. They can be extremely helpful in recording home invaders or car thieves.

However, some thieves are using handheld devices known to short-circuit those cameras.

Florham Park Police Lt. Brian Ford says of the devices that they are the “same size as a cellphone, could have several antennas coming out of it.”

Devices such as these can be purchased online for under $300.

Ford says that this past Monday someone tried to break into a home on Lincoln Avenue, not realizing the homeowner was in the basement. Ford says the homeowner heard someone trying to break in through a side door.

“When they tried to call us for help to respond to them, they were unable to use their phone,” says Ford. “They realized that their cameras in their home had gone down.”

Ford says the homeowner had to run to a neighbor for help.

Those who live in the neighborhood say they are now worried that the thieves could come back.

“That’s very scary. You’re in your house, you can’t call for help and you’re stuck there,” says neighbor Rick Zeien. “Everybody’s on alert, everyone is a little afraid.”

Police say they’re finding thieves are now setting up cameras in yards, on bushes or in yard ornaments. Ford says it’s their own form of surveillance.

“If they’re not going to physically watch people themselves then they can set up surveillance cameras in your yard and watch your routines,” he says.

Police say homeowners should check their bushes and property for unwanted cameras. They also urge homeowners to hardwire their security systems and not rely on Wi-Fi.