These witnesses, who included prominent global construction consultant Irv Richter, said they were quizzed about government contracts and campaign contributions, including alleged "straw contributions" designed to exceed finance-law limits.
Witnesses said they were asked about the dental executive, Candido Negron of Glen Mills, Delaware County. He raised tens of thousands of dollars for Acevedo-Vilá - and later unsuccessfully sought dental contracts in Puerto Rico.
Kenney, for example, said he told the grand jury that Negron asked him to write checks to Acevedo-Vilá, promising to reimburse him the next day. "Nice young man," he said of Negron.
The Kenneys contributed $11,000, records show.
"I got the money back right away. That was the only way I would do it," said Kenney, who said he did printing work for one of Negron's dental companies.
Interviewed at his home yesterday, Negron declined to comment. He said he was looking for a lawyer.
This Caribbean "pay-to-play" investigation, which began in 2005, routinely makes headlines in San Juan. Acevedo-Vilá's opponents have used it to urge him not to run for a second term; some supporters dismiss the probe as politically motivated.
Recently, the island's press has speculated that the investigation might end soon - the deadline for the governor to file for reelection is July 31. However, people familiar with the investigation doubt it will conclude until fall.
Luis S. Fraticelli, the FBI special agent in charge in San Juan, would not confirm that Acevedo-Vilá is under investigation.
But, speaking generally, he said it is not uncommon for some island residents to remain suspicious of U.S. investigations of Puerto Rican politicians.
"So it never fails that when the FBI investigates, or pushes for an indictment of a public official, generally someone in the press or public will label it as political," he said.
"Even with this local environment, we have a perfect 46-of-46 rate for convictions in corruption cases over the last 10 or 12 years."
Acevedo-Vilá has said he has done nothing wrong. "The truth will prevail," the governor said Monday, according to Reuters. "Two years have gone by and the only thing they've been able to do is spread rumors."
The governor's lawyer, Thomas C. Green of Washington, declined to comment.
From 2002 to 2004, Negron and Robert Feldman, the Philadelphia-based Democratic fund-raiser, raised tens of thousands of dollars for Acevedo-Vilá. Of the nearly $800,000 Acevedo-Vilá raised between 2001 and 2004, records show, roughly $180,000 came from Pennsylvania and New Jersey residents.
Negron and Feldman unsuccessfully sought a contract from the island's government health-care system for Doral Dental, a Wisconsin-based company that has paid them hundreds of thousands of dollars in commissions.
Feldman's lawyer, Henry E. Hockeimer Jr., declined to comment on the case. He has said Feldman has done nothing wrong.
Federal authorities suspect that some checks written during Acevedo-Vilá's 2002 congressional campaign - for Puerto Rico's nonvoting delegate - also were "straw contributions," donations made in the names of Philadelphia-area secretaries, administrators, and one office worker's mother to avoid finance limits.
Some area donors listed on Acevedo-Vilá's federal campaign reports for that year have told The Inquirer that they never contributed. Those donors were connected to Negron.
One reported $5,000 donor was a 71-year-old Germantown woman whose daughter worked for Negron. Her daughter told The Inquirer last year that her mother never made the contribution.
FBI agents have also questioned Judith Mondre, who owns a Philadelphia-based environmental consulting firm, said her lawyer, William DeStefano. She contributed about $3,000 to Acevedo-Vilá's campaign at about the same time she received a $100,000 contact with the island government.
"The FBI came to her house on a Sunday morning and asked if there was any linkage between the contributions and the contract," DeStefano said. "All the evidence shows that she absolutely did all the work and provided a fair value in return for her compensation, and that the work was beneficial to the government of Puerto Rico."
During his trip to San Juan a few months ago, Richter said he told the grand jury about an invitation to a Acevedo-Vilá campaign event organized by Feldman.
"I assume they brought everyone on the invitation list down to testify," said Richter, chairman of Hill International. "They asked about fund-raising and influence on the governor and his decision-making."
Richter said he testified that he didn't attend the fund-raiser, didn't contribute to Acevedo-Vilá, and didn't do business with his administration.
Of his testimony, he said: "It was a long trip for a short conversation."
Contact staff writer John Shiffman at 215-854-2658 or firstname.lastname@example.org.
Inquirer staff writer Mark Fazlollah contributed to this article.