WASHINGTON — A critical network of cameras and sensors installed for the U.S. Border Patrol along the Mexican and Canadian borders has been hobbled for years by defective equipment that was poorly installed, and by lax oversight by government officials who failed to properly supervise the project's contractor, according to government reports and public and industry officials.

The problems with the $239 million Integrated Surveillance Intelligence System (ISIS), which U.S. officials call crucial to defending the country against terrorist infiltrators, are under investigation by the inspector general of the General Services Administration.

The investigation into whether government officials allowed the contractor to cut corners on the project and receive huge overcharges could lead to administrative or criminal charges, the officials said. Perhaps tens of millions of dollars were wasted on the system of 12,000 sensors and several hundred cameras installed for the Border Patrol between 1998 and last year, the GSA suggested.

Many irregularities were documented in a scathing GSA inspector general's report, released in December, which cited millions of dollars in potential overcharges by the contractor, International Microwave Corp. (IMC), as well as the record of U.S. officials paying for work that was never done.

Investigators are looking into the past activities of the Connecticut-based firm, as well as the actions of some current and former officials of the Border Patrol; its former parent agency, the Immigration and Naturalization Service; and the GSA.

Many of the ISIS cameras, which are placed on 50- to 80-foot poles, break down frequently. The wiring of the electronic system on the Canadian border with Washington state is so slapdash that cameras there often jerk randomly in warm weather.

"The contractor sold us a bill of goods, and no one in the Border Patrol and INS was watching," said Carey James, the Border Patrol chief in Washington state until 2001. "All these failures placed Americans in danger."

Controversy about the project led U.S. officials to stop almost all work on ISIS about 16 months ago, officials said.

Officials at the Department of Homeland Security, now the parent of the Border Patrol, acknowledge there were serious technical and oversight problems with the ISIS program.

Homeland Security officials say the ISIS network is helpful in spotting intruders and guiding border agents in pursuit, but needs to be expanded. It covers only a few hundred miles of the 6,500-mile Canadian and Mexican borders.

Roger Schneidau, who helps run the Border Patrol's electronic-barrier programs, said that "there are sites in varying need of repair," but that in places where the equipment is available and working, "it's incredibly useful to agents."

Anthony Acri, IMC's president until 2003, said the ISIS system is well-built and was a good investment for taxpayers. He said oversight by U.S. officials was proper and effective. Acri said the halt in work on ISIS "is very dangerous for our country."

Many — but not all — of the system's problems have been resolved in the past year by repair work done by L-3 Communications, a New York company that bought IMC in 2003, officials said. L-3 officials fired some of IMC's executives, including Acri, industry executives said.

The story of the ISIS network is a tale of wasted taxpayer money and bureaucratic dysfunction.

The GSA inspector general's report said official inattention to the system "placed taxpayers' dollars and ... national security at risk." A GSA inspection of eight Border Patrol zones found that $20 million had been paid to IMC for work there, but that none of its camera systems was fully operating.

Near Buffalo, N.Y., the company billed the government for 59 cameras but only four were installed. In Naco, Ariz., unassembled high-tech gear was found lying in the desert, the report said. "No IMC personnel had been on-site since the equipment was delivered" in 2003, it added.

The most troubled part of the ISIS network was in Washington, where the more than 64 cameras fogged up in cold and rain and sometimes broke down completely, according to Border Patrol officials and the GSA report. Workers hired by IMC had done such a poor job of installing fiber-optic cable that Border Patrol operators couldn't control the cameras, according to officials and documents. Electrical wires were found corroding under water in supposedly sealed concrete vaults, they said.

The GSA inspector general's report found that IMC was paid about $1 million up front to install 36 poles to hold multiple cameras in Washington state, but in fact had installed only 32. Contract documents executed by both the GSA and the company "misrepresented the work that was actually furnished," it said.

It was common, the report said, for the government to pay IMC "for shoddy work ... [or] for work that was incomplete or never delivered."

Acri said the Washington project was "a nightmare," but blamed it on miscommunications with Border Patrol officials. L-3 has fixed many of the problems there recently, but Border Patrol agents still complain of malfunctions and blind spots.

The GSA inspector general's report also sharply criticized operations at a Border Patrol repair center in New Mexico staffed by two Border Patrol officials and 19 IMC employees. Many Border Patrol agents complained that repairs on the ISIS equipment took months to complete.

The report said "little or no work" was done at the center in the previous year, even though IMC billed the government for $500,000 during that time. The report said millions of dollars in overcharges might have occurred there.

The GSA inspector general's report and numerous government and industry executives said government officials often deferred to IMC in deciding what equipment to buy and how much to pay. The report said IMC's contracts with the government lacked detail, "thereby leaving interpretation of the government's needs up to the contractor."

"Government officials failed miserably to do their job," said Tim Golden, an IMC subcontractor on the program who later had a falling out with the company. "It's incomprehensible how inept they were."

Many ISIS documents were drawn up in such a way that the company was paid up front, and escaped financial liability if its performance was disputed, said the GSA report and U.S. officials.

Over the objections of Border Patrol officials, INS official Walter Drabik chose cameras distributed by a firm called ISAP. Government officials and contractors said IMC had bought ISAP without disclosing it to government officials. This allowed IMC to buy cameras from its own subsidiary, substantially increasing profits.

Early last year, a small group of Border Patrol officials drew up plans for a far more ambitious, multibillion-dollar project under which a contractor would cover the nation's land borders with an expanded network of cameras, sensors and high-tech devices.

The new project, called America's Shield Initiative (ASI), was enthusiastically endorsed in Congress and by the Bush administration.

"We've identified the problems; they're very evident," said Border Patrol's Schneidau. "We're taking steps to prevent them from happening again."