WASHINGTON (CNN) -- The National Counterterrorism Center is disputing charges that the computer system that compiles information on terrorists and suspected terrorists from government agencies is ineffective and hindering its ability to track terrorists.
"There has been no degradation in the capability to access, manage and share terrorist information," the center said in a statement on Friday.
Rep. Brad Miller, D-North Carolina, is asking for an investigation into the center's computer systems. Miller says that half a billion dollars has been spent on a computer upgrade that is riddled with flaws.
"It's been seven years since 9/11, and we appear to be no better prepared, no better able to connect the dots than we were seven years ago," Miller said.
The computer system is used to create government watch lists and provides information to federal, state and local officials.
According to a congressional staff report prepared by Miller's House Subcommittee on Investigations and Oversight, the system put in place after the September 11 attacks has limitations that make it difficult to search or locate key data.
For instance, the report says, information about "pocket litter" -- the scraps of paper in a suspect's pocket that can yield important clues like phone numbers, credit cards and addresses -- is contained in 23 tables rather than just one.
The report says the system upgrade, called Railhead, does not have the ability to search e-mails and discussion threads, images or attachments.
In tests, it couldn't match different spellings of suspected terrorists' names, a common problem associated with translating Arabic names into English. And it will not connect to intelligence community Web sites like the CIA, the FBI and the National Security Agency.
"It's like having a dictionary without it being in alphabetical order," Miller said. "The information may be there; you just can't find it."
In its statement, the center said regular reviews have identified program shortcomings that have been quickly addressed. It noted that the House and Senate intelligence committees have been briefed multiple times and that the program has received congressional support.
"Representative Miller's Subcommittee has had no interaction with the NCTC or the Intelligence Community on the Railhead Program," the statement said.