Two former New Jersey attorneys general on Thursday defended their office’s investigation into the political dealings of George E. Norcross III, the Democratic power broker, and said they were bewildered that federal prosecutors had accused them of botching the case.In a scathing letter dated Tuesday, Christopher J. Christie, the United States attorney for New Jersey, wrote that his office would be unable to bring charges against Mr. Norcross because lawyers for the state attorney general had mishandled their investigation under two administrations before turning it over to his office in 2004.

Mr. Christie’s pointed critique startled many in the legal community because prosecutors rarely publicly criticize other law enforcement officials or explain their decisions not to prosecute.

While Mr. Christie did not release the letter to the press, his office did give it to two witnesses whose complaints against Mr. Norcross led to the investigation, and who have been aggressive in seeking news coverage about the case.

In his six-page letter, Mr. Christie chastised state officials for failing to use rudimentary investigative techniques like wiretaps and telephone records to corroborate their suspicions that Mr. Norcross and his political allies were engaged in a plot to deprive two political rivals of jobs and government contracts.

His letter also harshly criticized state prosecutors for deciding not to secretly tape conversations at a Camden County Democratic fund-raiser in 2001, where Mr. Norcross and his associates were expected to discuss a wide variety of political deals. Mr. Christie said that that decision was so inexplicable that it raised the possibility that state investigators were trying to shield political figures.

But John J. Farmer Jr., who was attorney general in 2001, called that suggestion ”utter nonsense.” Mr. Farmer said he was not personally involved in the tactical decisions, but asserted that the two assistant attorneys general who led the case were ”professional and 100 percent nonpolitical.”

”I totally reject any suggestion that any political figure was being protected by anyone in my office,” said Mr. Farmer, a political independent who worked for Govs. Christine Todd Whitman and Donald T. DiFrancesco, both Republicans.

Mr. Christie also said that former Attorney General Peter C. Harvey erred in 2003 when he agreed to allow two figures in the investigation to plead guilty to tax evasion charges, a deal Mr. Christie said was too lenient to yield meaningful cooperation.

But Mr. Harvey said the agreements were fair and helpful. ”These plea agreements were negotiated by experienced former federal prosecutors and helped lead to other convictions in this case,” he said.

The investigation and secret recordings of Mr. Norcross, a bank executive whose prowess as a fund-raiser has given him vast statewide influence, has offered a rare view of the inner workings of New Jersey’s tough, money-driven politics.

The case began in 2000, when John Gural, now the mayor of Palmyra but then a councilman, told the authorities that he had been pressured to fire the town solicitor, Ted Rosenberg, who had opposed one of Mr. Norcross’s allies in a local political race.

Investigators from the state attorney general’s office asked Mr. Gural to wear a concealed recording device. He ended up taping more than 330 hours of conversations, many of them with local officials allied with Mr. Norcross. In some of those conversations, they threatened to withhold government contracts from Mr. Gural’s employer, a local engineering firm, unless he acquiesced.

Mr. Norcross was also caught on tape boasting about his influence with then-Gov. James E. McGreevey and then United States Senator Jon S. Corzine.

Mr. Norcross’s lawyer dismissed his client’s taped comments as idle boasts, and said that Mr. Christie’s letter was proof that no crime had been committed.

Mr. Rosenberg said on Thursday that Mr. Christie, who has been mentioned as a candidate for governor himself, might have released the letter to protect his image as an ardent corruption buster.

”Chris Christie is first and foremost a political animal,” Mr. Rosenberg said. ”He gave us the letter and didn’t say anything about keeping it private, so of course we gave it to the media. The way he handled this he was freed of any responsibility for letting George Norcross get off of the hook.”

But in an interview on Thursday, Mr. Christie said he was proud of his record. Since being appointed United States attorney in 2002, he said he had brought public corruption charges against nearly 100 people. He said he felt that the attorney general’s office deserved a detailed explanation of why he was not pursing charges, since Mr. Harvey publicly referred the case to him in 2003
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