Mr. Tivol said the goal was to provide a match with an 80 percent to 90 percent certainty from a range of up to 100 meters, something “that has never been done.” While the system continued to have problems with light and shading in some tests, he said, in others the goal had been achieved at closer distances. Farther away, he said, the accuracy has fallen to 60 percent to 70 percent.

“The results were increasingly positive,” he said. There was a “significant improvement” in speed, too, he said. At first, it took the system six to eight minutes to process images, but it now takes under 30 seconds.

Still, he and Dr. Farag said, the officials overseeing the testing wanted a quicker turnaround. That might be easier with the more powerful computers available to the military, they said, but the government wanted them to use processors available off the shelf for civilian applications.

Several independent biometric specialists, given a description of the project’s test results, agreed that the system was not yet ready. They said 30 seconds was far too long to process an image for security purposes, and that its accuracy numbers would result in the police going out to question too many innocent people.

Several of the specialists also suggested that similar technology may be progressing more quickly in other laboratories that have not received taxpayer financing. A spokesman for Mr. McConnell stressed that while he requested that the contract go to Electronic Warfare Associates, it was “competitively bid.” Federal records show the firm was the only one to submit a bid.

Ginger McCall, a privacy advocate who obtained the documents under the Freedom of Information Act and provided them to The New York Times, said the time was now — while such technology is still maturing and not yet deployed — to build in rules for how it may be used. (Ms. McCall was at the Electronic Privacy Information Center at the time of her information act request.)

“This technology is always billed as antiterrorism, but then it drifts into other applications,” Ms. McCall said. “We need a real conversation about whether and how we want this technology to be used, and now is the time for that debate.”