At a hearing on HUD's budget, Specter said the dispute between the department and PHA - involving a federal lawsuit, an inspector general's investigation, and flippantly worded HUD e-mails that were leaked to the press - had turned "rancorous, cantankerous . . . involving very sharp accusations."

In the lawsuit, PHA director Carl Greene maintains that the funding freeze was punishment for his refusal to grant, at virtually no cost, four South Philadelphia properties valued at $7 million to Universal Community Homes. The development group is led by R&B songwriting legend Kenny Gamble, a friend to Jackson and former Mayor John F. Street.

The suit contends that Jackson called Street to try to get him to intervene with Greene on Gamble's behalf.

Gamble, inducted Monday into the Rock and Roll Hall of Fame, declined to comment yesterday.

The e-mails between two senior HUD officials on Jan. 7, 2007, were pried loose in legal discovery for the federal lawsuit. Specter said they "raise suspicions" that something in the HUD process was "amiss."

"Would you like me to make his life less happy? If so, how?" wrote Orlando Cabrera, then an assistant secretary for public housing, referring to Greene.

"Take away all his federal dollars," replied Kim Kendrick, an assistant secretary for fair housing and equal opportunity, ending her message with a smiley icon.

"Let me look into that possibility," Cabrera typed back.

Later that day, the funding was suspended, a twist of timing that Specter said seemed "an extraordinary coincidence, if not causally connected."

Jackson said the language in the e-mails reflected the writers' general frustrations.

Specter wasn't buying it.

"That's just too much of a coincidence," he said. "It all happens on the same day. These aren't collateral frustrations of something else. This is simultaneous. That kind of timing is very, very forceful evidence."

Jackson yesterday had been scheduled to present prepared remarks about his agency's general performance and priorities. His statement said he would take written questions.

A grim-faced Specter, however, let him know there would be more on the agenda.

"That is not satisfactory," Specter said. "This is a subcommittee of the United States Senate charged with putting up billions of dollars for your department. There are very important questions that have to be answered. . . .

"When I wrote you yesterday, I scratched off 'Mr. Secretary' and I put 'Al.' Signed it 'Arlen.' Because you and I have an 'Al and Arlen' relationship. But with $50 million and the kind of allegations that are involved here, we have to get to the bottom of this."

For the next eight minutes, Specter grilled the secretary.

Jackson said he had called Street to discuss completion of the adjacent public-housing project in South Philadelphia, not to talk about Universal's unhappiness with not getting the parcels it desired.

Badgered by Specter, an exasperated Jackson said: "Senator, I have told you the truth. . . . I have not lied to you."

Asked if anyone from Universal had contacted him to express displeasure over the parcels, Jackson paused for seven seconds before answering:

"If they did. I can't. I really. I don't think. I just can't remember," he said.

"Is it a possibility that they did?" Specter asked.

"I can't remember," Jackson replied.

The four parcels are two vacant lots near 13th and Bainbridge Streets, a shuttered community center at 13th and Fitzwater Streets, and a vacant block at 12th and Catharine Streets.

Asked what reason Cabrera could have had for making Greene's life "less happy," Jackson said Specter would have to ask Cabrera, who has left HUD.

"Oh, I will," said Specter, keeping up the attack and promising to invite all relevant parties to a meeting.

Later, as Specter walked to the Senate chamber to vote on an unrelated matter, he said he wanted to settle this dispute before the taxpayer-borne costs of litigation went any higher. He said he believed he might bring about a resolution if he could confront Cabrera, Kendrick and Jackson simultaneously.

"I don't want to talk to them one at a time. I want the three of them in a room," he said.

While saying he does not want to air dirty linen, Specter yesterday offered just a whiff of how contentious his battle to force HUD to reconsider will be.

"There are a lot of very serious charges being made against HUD here," he said after the hearing. "When you see the sequence of those e-mails, it looks like there is something to Greene's point about retaliation."

Stephen O'Halloran, a spokesman for Jackson, said the housing secretary did not want to add to his public comments on the matter.

Inquirer staff writers Jeff Shields and Jennifer Lin contributed to this article.