Vincent C. Gray took office with great expectations and the general goodwill of the city. But a Washington Post poll in June found that trust in him has eroded since Brown’s allegations became public and the U.S. attorney’s office began its investigation. (Bill O'Leary/The Post)

Federal investigators digging into irregularities in the campaign of Mayor Vincent C. Gray have interviewed several of his associates and election staff members, subpoenaed reams of documents, and granted immunity to at least one witness who testified before a grand jury, according to nearly a dozen people familiar with the probe.

The criminal probe began after onetime mayoral candidate Sulaimon Brown alleged in March that he was paid by the Gray campaign to disparage then-Mayor Adrian M. Fenty during last year’s Democratic primary. Brown also claims that the Gray campaign promised him a city job in return for his political attacks on Fenty.

In addition to Brown’s allegations, investigators are examining possible irregularities in money-order donations to Gray’s campaign, some of which appear to have violated city campaign regulations, the sources said.

The mayor and senior campaign staff members have denied any wrongdoing related to either Brown’s allegations or the money-order donations.

Through their questioning of campaign staff members and their interest in campaign documents, investigators appear to be focusing on consultant Howard L. Brooks and possibly others in the Gray campaign, said two sources with knowledge of the probe.

Authorities are trying to determine whether Brooks, a close friend of Gray campaign Chairwoman Lorraine A. Green’s, passed Brown the alleged payments. Brooks and Green have denied any wrongdoing.

Federal investigators have secured fingerprints from Brown and Brooks, according to people with direct knowledge of the probe, who spoke anonymously because they are not authorized to talk publicly about the investigation. It could not be learned who else has been asked to submit fingerprints. The fingerprints could help identify anyone who might have handled documents, money orders or envelopes with cash that Brown claims the Gray campaign gave him or who might have handled apparently fraudulent money-order donations to the mayor’s campaign.

Gray took office with great expectations and the general goodwill of the city. But a Washington Post poll in June found that trust in him has eroded since Brown’s allegations became public and the U.S. attorney’s office began its investigation. Gray has stumbled in hiring staff — missteps at times magnified by ongoing investigations, including one by a congressional oversight committee.

With federal authorities asking questions across the city and presenting their case to a grand jury, Gray’s administration remains under considerable scrutiny.

U.S. Attorney Ronald C. Machen Jr. declined to be interviewed about the investigation. But his spokesman, Bill Miller, said, “We are continuing to look into this.”

Federal authorities want to determine whether there was a quid pro quo when the administration hired Brown as a $110,000-a-year special assistant in the Department of Health Care Finance and whether contributions were illegally funneled to Gray’s and Brown’s campaigns, the sources said.

Gray has said that he promised Brown a job interview, not a job, and that the offer was not made in return for attacks on Fenty.

The grand jury

According to sources with knowledge of the investigation, witnesses who have testified before the grand jury include Peyton M. Brooks, Brooks’s son, and Ken Cummins, whose firm conducted background checks on job candidates for Gray’s transition team.

Two other sources said that Peyton Brooks received immunity from federal prosecutors months ago in return for his cooperation with the investigation. Like Brown, Peyton Brooks landed a $110,000-a-year special assistant job with the District, but he resigned after allegations of nepotism and cronyism were aimed at the Gray administration. The administration initially hired the children of several campaign and administration staff members.

Troy W. Poole, Brooks’s attorney, declined to comment about the investigation or his client’s testimony. “I’m not going to discuss what immunity my client may or may not have with the prosecution,” he said. “I want to make it clear that my client is not a subject or a target of this investigation.”

Howard Brooks declined to comment through his attorney, former Prince George’s County state’s attorney Glenn F. Ivey. Cummins also declined to comment.

Several sources confirmed that HowardBrooks and Brown have submitted fingerprints to investigators, but Lorraine Green’s attorney, Thomas C. Green, said his client had not submitted fingerprints. Asked whether she had been asked to, he said, “I’m not going to get into that.”

But Thomas Green, who is not related to his client, said she provided investigators with documents on the vetting of job candidates for Gray’s administration as well as her e-mails. Brown was among some of the earliest candidates considered for jobs in the administration.

Robert S. Bennett, Gray’s attorney, declined to comment on details of the case, including whether the mayor has submitted fingerprints. “I don’t want to go into detail, but I’ve talked to lots of folks,” said Bennett, who added that he is conducting his own investigation. “Gray did nothing wrong. I’m just hopeful that they [federal prosecutors] conclude that very quickly. . . . This is a cloud over the city.”

James W. Rudasill Jr., Brown’s attorney, declined to discuss his client’s cooperation with investigators. However, Brown said in open court that the federal grand jury had subpoenaed copies of documents, which the subpoena said included checks, money orders or anything of value from Gray or Gray’s staff from his campaign, transition or administration. He was in court because of a D.C. Council subpoena for similar records. Brown told the judge that he had given his records to investigators, and he told The Post that federal authorities also had his three cellphones.

The Post reported in March that Brown’s phone records showed that he often communicated with members of the Gray campaign — including personal assistant Stephanie Reich — and that several of his calls were returned.

“What my client is saying can be substantiated,” Rudasill said.

According to several sources with knowledge of the federal probe, Reich has been interviewed by the U.S. attorney’s office. She declined to comment.

Paper trail

According to sources familiar with the probe, the grand jury heard testimony in August from Cummins, president of Capitol Inquiry, a private investigation firm that did background checks for Gray’s administration. Cummins turned over his records and e-mails to federal prosecutors in April, the sources said.

Capitol Inquiry managed the background checks. Cummins communicated directly with Green, who also headed the Gray transition team. Capitol Inquiry investigated Brown in January, shortly before he was hired by the administration. The background check detected some of Brown’s past legal and financial troubles before he was hired.

In testimony before the D.C. Council this summer, Green acknowledged that she met with Brown at Union Station in 2010, when he claims she handed him an envelope containing about $750 in cash. Green has disputed Brown’s account. She denies that any payment was made and says she only talked to him about consideration for a job. Brown says that Brooks delivered payments later in the campaign.

The Post reported in March on an exchange of text messages in November 2010 between Brown and Gray about an “agreement.” The mayor said any agreement referred only to a job interview.

Campaign volunteers, who spoke on the condition of anonymity because they fear retaliation, told The Post that the campaign invited Brown to some Gray political events. At one of those events, a fundraiser at the Eatonville restaurant, Brown said Gray told him that Brooks has “something for you,” according to his testimony in June before the D.C. Council. Brown says that Brooks delivered another payment at the event.

Photos of the event place Brown, Brooks, Green and Gray at Eatonville, but Gray has denied such an exchange took place.

The donations

Several sources also said the federal investigators are trying to determine who signed money-order donations to the Gray and Brown campaigns in apparent violation of campaign rules.

The Post reported in July that Gray’s campaign had accepted cash contributions above the $24.99 legal limit as well as money-order contributions purportedly from people who have denied contributing to the campaign. Since then, The Post has found that the campaign documented in finance reports more than 100 cash contributions of $25 or more. Interviews with some contributors also showed that the Gray campaign had turned cash into money orders, often in violation of city laws that prohibit doing so.

The sources said the FBI has confirmed that signatures on some money orders were forged. Also of interest to investigators are some money orders that allegedly were signed by the same person and others that are numbered in sequence, which indicates that they were purchased at the same place and time, one source said.

Brown’s campaign received hundreds of dollars in money-order donations allegedly signed by people with ties to Howard Brooks, including son Peyton, Peyton’s girlfriend and a cousin by marriage. The money orders credited to Peyton Brooks were purchased at Safeway and are sequential.

The records also show that on June 1, 2010, the campaign received one $2,000 money order from Howard Brooks and another from Leroy Ellis. Ellis, a friend of Brooks’s, was hired as a $125,000 city employee after Gray took office. Ellis was recently laid off because of budget cuts, according to the administration, and did not respond to calls or an e-mail seeking comment.

Campaign finances were handled by Thomas W. Gore, a longtime friend of Gray’s, and Reuben O. Charles II, who quickly rose through the campaign ranks because of his fundraising abilities.

Gore worked closely with Brooks, Gerri Mason Hall, a campaign consultant who became Gray’s first chief of staff, said in testimony before the D.C. Council.

Two campaign staff members said that Gore was aware of questionable cash donations to the campaign. One source said he told volunteers and staff members, including Brooks, to return them. Other sources previously said he had distributed the campaign finance rules to campaign workers. According to several sources, Gore has been interviewed by federal investigators.

Gore’s attorney, Frederick Cooke Jr., declined to comment. Charles did not respond to calls seeking comment.

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