SAN FRANCISCO—Federal prosecutors in San Francisco dropped their 4 1/2-year-old political corruption investigation of former California Senate leader Don Perata, but government attorneys in Sacramento are now pursuing the case, his attorney said Wednesday.

Perata attorney George L. O'Connell said he met with Sacramento prosecutors in late December and early January but they gave him no explanation for why they were taking over the case. O'Connell said he had "serious concerns" the government is moving too rapidly toward bringing charges.

"The Eastern District is moving ahead very quickly and has not given an indication they're ready to pull the trigger," he said in a phone interview. "They are rushing the case ... not taking the care this type of case would warrant."

Lawrence Brown, the acting U.S. Attorney in Sacramento, said the FBI approached his office in the fall to review the case.

"This was not done at our initiation," said Brown, who took over the office when McGregor Scott resigned at the beginning of the year.

Scott said that two experienced prosecutors of political corruption cases urged him to look into the case after FBI agents investigating Perata approached them.

Scott said he agreed "out of an abundance of caution" to examine the Perata matter. Scott, a Republican appointee, also denied claims from Perata's camp that politics played any role in picking up the probe of Perata, a prominent Democrat.

"If that were the case, we would have indicted him before I left office," Scott said.

The U.S. Attorney's office in San Francisco declined comment.

In a letter to U.S. House Judiciary members on Wednesday, O'Connell said the federal government's actions are unjust and he asked the committee to investigate.

A federal grand jury has been conducting a sprawling examination of the East Bay Democrat's business dealings, and FBI agents have interviewed political allies and campaign contributors who may have benefited from his influence. The grand jury has taken testimony and received thousands of pages of documents from government agencies that had dealings with Perata, who was termed out of office in 2008.

The conflict-of-interest investigation also has caught up an Oakland lobbyist, campaign consultants and Perata's son, Nick.

Nick Perata's attorney, Elliot Peters, said Dave Anderson, the second-highest ranking federal prosecutor in the San Francisco U.S. attorney's office, told him that office was declining to pursue a grand jury indictment. Meanwhile, Peters said, the Sacramento office said it was taking over the investigation.

"I really think the DOJ should speak with one voice," Peters said.

Peters sent a letter to U.S. Attorney General Eric Holder complaining that he and his client had agreed to waive the statute of limitations to allow the San Francisco prosecutors time to complete the investigation and hear from the defense. Peters complained those agreements were now being unfairly exploited by prosecutors in Sacramento.

Acting U.S. Attorney Brown said the agreements apply to the entire Justice Department.

The complex investigation has been under way since 2004.

The investigation has revolved around the flow of money between outside entities seeking to curry favor with decision-makers, Perata's friends and family, and the senator himself.

Among the questions is whether Perata received payments from firms operated by family and friends. In some cases, those firms had received payments from his campaign committees for what had been described as political consulting work.

Prosecutors also examined whether Perata helped steer political consulting work to his family and friends, and whether any of that money was later kicked back to Perata.

In 2005, the grand jury issued a subpoena seeking e-mails from Perata and eight staffers dating back six years.

O'Connell said federal prosecutors repeatedly told him that the probe had found no evidence of bribe payments.

"Over the last five years, Sen. Perata and his family have suffered irreparable harm to their personal reputations due to an investigation with no clear purpose or direction," Perata spokesman Jason Kinney said. "It's time to bring this unjust folly to an end."