In the hours after the Sept. 11 attacks, Asher created a prototype at Seisint Inc., the Boca Raton, Fla., information service he founded. It generated the names of thousands of people he thought might be worth the attention of authorities. The tool called "high terrorist factor," which relied on intelligence and profiling, was later withdrawn from the system, Asher said.

The Florida Department of Law Enforcement soon became the lead agency in expanding Matrix and the Justice Department pledged $4 million to improve the system and widen its reach. Initially, 16 states agreed to contribute and draw information from Matrix, but 11 did not follow through or dropped out, citing civil liberties concerns or cost. Currently participating are Florida, Michigan, Ohio, Pennsylvania and Connecticut.

Organizers intend to ask other data services for proposals to create other Matrix-like systems later this year, in part to create competition, said Mark Zadra of the Florida department. Currently, Matrix operates under a sole-source contract with Florida.

Questions about Asher's past created controversy when the program became public last year. Confidential Florida police documents said he had been involved in drug smuggling in the early 1980s. Asher confirmed that he had limited involvement as a pilot for a few months, but police reports said he was never arrested or charged.

The ACLU and other critics say Matrix gives the government too much power to examine the lives of individuals through a process called data mining. Steinhardt said the government should not be deeply involved without a thorough examination of the implications. "It's a very dangerous marriage," he said.

Asher spent millions of his own money to refine the Matrix system. Asher said he wanted to find accomplices of the 9/11 hijackers and help authorities prevent terrorist attacks before they occur. He said Matrix does what authorities have repeatedly said needs to be done: connect the dots between suspects. "I did this because I thought we were in the middle of a world war," he said yesterday. "That it has drawn so much criticism makes me believe the country does not have its eye on the ball."

The White House meeting was a key moment for Matrix. Asher's work had already drawn the attention of senior authorities from the Justice Department, FBI, Secret Service and intelligence agencies by using Matrix to generate thousands of potential suspects, many of them Muslims.

Not long after the Sept. 11 attacks, Asher generated a list of 120,000 names, most of which he said had nothing to do with terrorism. Asher said he then cut it to about 1,200 names, something known as the "1 percent list," which provided leads in scores of investigations, some of which led to arrests.

Unknown to Asher at the time, he said, five of the names he generated were hijackers on the planes.