Paone said the three subpoenas issued yesterday were part of an investigation that began earlier this year. He said authority officials discovered contracting irregularities about seven months ago and the investigation had since widened.
Following PHA's own internal investigation, two PHA employees were fired after it was discovered that they were part of a scheme to enter false bids on repair work, allowing favored companies to win contracts, according to authority officials.
Paone declined to say what evidence the authority discovered but said "we were sufficiently concerned to turn it over" to federal investigators.
"The housing authority was the initiator of this investigation and has cooperated fully," Paone said.
Paone said the contracting problems at the authority could be widespread. ''It could be endemic to the organization," he said. Paone said that he did not know exactly who in the agency was being investigated and that "we do not have enough proof" to fire any other employees.
Courtenay Cannady, a spokeswoman for the authority, said that as a result of the inquiry, four contractors had been suspended from further work with the authority pending the outcome of the investigation.
The authority awards about $50 million in repair and construction contracts a year. The subpoenas sought documents of the authority's central maintenance office and its design and construction division.
Federal audits of the housing authority have repeatedly found problems with the agency's method of purchasing services. An audit issued in March by investigators from the Department of Housing and Urban Development found that the authority grossly overpaid for repair work and that contractors performed work that was never ordered and did not perform work that was ordered.
PHA officials said they had made changes in their organization to correct problems found in the audit.