The so-called "virtual fence" along the Arizona-Mexico border is under assault, and not by people illegally crossing the border.

Four years ago, the high-tech surveillance system was set up near the towns of Sasabe and Arivaca in southern Arizona. It was meant to guard against all kinds of illegal border crossings, but critics say the Homeland Security program was a huge waste of money and hasn't shown results.

Back in 2006, Homeland Security hired Boeing to build the surveillance system, but the project had technical issues from the start. Not only that, but critics have questioned the hefty cost -- more than a billion dollars so far.

Now, the virtual fence seems to be nearing its end. Reports out Friday suggest Homeland Security will be scrapping the virtual fence altogether, and some people aren't happy about that.

Each tower in the southern Arizona desert has a radar system and a series of cameras that work day and night. They're used to spot and track illegal immigrants and smugglers.

Those towers were supposed to go up all along the 2,000-mile border with Mexico, but so far, there are only a few dozen built.

Near those border towns, the virtual fence gets mixed reviews.

"I think it's a money pit, they never work everything is offline," says Ginger Dunn.

"Not accomplishing what they wanted it to and they don't keep it funded appropriately."

But some say these towers have deterred illegal crossings .

Terry Tompkins hopes the feds don't put an end to the virtual fence program.

'It's changed a lot of the patterns of the people that are going through the area. I don't know whether that's enabled Border Patrol to set up catch points, but it's changed routes people have used."

When the radar picks up on undocumented immigrants, it maps their location and takes an image which is sent to Border Patrol. Many agents have found the virtual fence program, officially called SBI-net, a helpful tool.

Boeing, who designed these surveillance towers, gave us this statement: "Boeing stands behind its work on the SBI-net system as a reliable, effective border security tool."

Earlier this year, Homeland Security Secretary Janet Napolitano froze funding for the virtual fence, and the program is currently under review.

The feds may pull the plug on the high-tech border security system -- the contract with Boeing only lasts until next month.

If Homeland Security decides to continue building the virtual fence along the entire border, it would cost about $8 billion and be finished by 2017.

There's no word when the final decision will be made.

This story was filed by Alex Savidge for KSAZ in Arizona. For more information visit myfoxphoenix.com