Metro said it has revised its rules to require at least three competitive bids for certain contracts after an outside audit found the agency violated federal rules.

The independent auditing firm CliftonLarsonAllen found that Metro failed to follow federal contracting requirements when it used $5 million in federal stimulus money in the award of a contract worth more than $12 million to a McLean-based company.

Metro was required to seek offers from at least three sources, according to the audit findings presented to board members Thursday. But the agency failed to document that it had other bidders on the contract.

Now the audit must be sent to the Federal Transit Administration for review. It was not clear Thursday, though, what punishment -- if any -- Metro could face. The FTA declined to comment. It also could take a while to get any answers, as the audit is not due to the FTA until the end of March, according to the auditing firm.

The news comes amid an ongoing investigation by the Department of Transportation's Inspector General's Office into the same contract, as The Washington Examiner first reported in August.

The auditors also found problems with work done as part of the project, including inconsistencies in documentation used to make key decisions.

They said Metro relied on the contractor to control some of the system's security, too, even after the system was launched. Such security should have been handled internally.

Metro agreed with the firm's findings and said it has revised its procurement manual to require at least three proposals for any competitive bidding of this kind. It also said it will create new documentation standards by Jan. 31 and has hired a staffer to address security issues.

The contract given to information-technology consultant firm Metaformers was intended to help integrate two systems that Metro uses to track its financial systems and its business processes.

The $9.15 million Metaformers contract was awarded in June 2010 for a two-year period, according to contract documents.In April 2011, the contract amount was increased to $9.79 million. And in July 2011, Metro exercised another option, bringing the total to $12.4 million.

The auditors were paid by Metro to review the agency's books as part of an annual review. The Metaformers contract was one of several contracts the auditors reviewed out of a sample, said CliftonLarsonAllen partner Mike Stephens.