Senator Carl Levin, the Michigan Democrat who is chairman of the Armed Services Committee, said in a statement that it was worth “looking into why Blackwater would need to create the dozens of other names” and said he had requested that the Justice Department investigate whether Blackwater officers misled the government when using subsidiaries to solicit contracts.

The C.I.A.’s continuing relationship with the company, which recently was awarded a $100 million contract to provide security at agency bases in Afghanistan, has drawn harsh criticism from some members of Congress, who argue that the company’s tarnished record should preclude it from such work. At least two of the Blackwater-affiliated companies, XPG and Greystone, obtained secret contracts from the agency, according to interviews with a half dozen former Blackwater officials.

A C.I.A. spokesman, Paul Gimigliano, said that Xe’s current duties for the agency were to provide security for agency operatives. Contractors “do the tasks we ask them to do in strict accord with the law; they are supervised by C.I.A. staff officers; and they are held to the highest standards of conduct” he said. “As for Xe specifically, they help provide security in tough environments, an assignment at which their people have shown both skill and courage.”

Congress began to investigate the affiliated companies last year, after the shooting deaths of two Afghans by Blackwater security personnel working for a subsidiary named Paravant, which had obtained Pentagon contracts in Afghanistan. In a Senate hearing earlier this year, Army officials said that when they awarded the contract to Paravant for training of the Afghan Army, they had no idea that the business was part of Blackwater.

While Congressional investigators have identified other Blackwater-linked businesses, it was not the focus of their inquiry to determine how much money from government contracts flowed through the web of corporations, especially money earmarked for clandestine programs. The former company officials say that Greystone did extensive work for the intelligence community, though they did not describe the nature of the activities. The firm was incorporated in Barbados for tax purposes, but had executives who worked at Blackwater’s headquarters in North Carolina.