The fallout from a damaging report by Attorney General Cuomo’s office detailing the Spitzer administration’s use of state police for political attack purposes is likely to spread, threatening to upend Governor Spitzer’s agenda and bring down his most senior adviser.

After a three-week investigation, Mr. Cuomo’s office yesterday released a 53-page report accusing Mr. Spitzer’s communications director, Darren Dopp, and a top state homeland security official of ordering state police to take extraordinary measures to track the use of air and ground police escorts by the Republican Senate majority leader, Joseph Bruno, in an effort to catch him abusing state resources.

Mr. Spitzer, who suspended Mr. Dopp and reassigned the other official, insisted he was unaware of the plot to discredit Mr. Bruno in the press. Senate Republicans, however, signaled they would launch their own probe into the matter, raising the possibility that they would use the subpoena power of standing committees to try to uncover e-mails and investigative transcripts implicating other high-level administration staffers, including Mr. Spitzer’s top adviser, Secretary Richard Baum, and the governor himself.

“What did the governor know, and when did he know it?” a Republican state senator of Brooklyn, Martin Golden, said. “There should be a further investigation into the inner circle. Somebody signed off on this. I urge the governor to get to the bottom of this.”

The report does not call for any disciplinary action against Mr. Baum, but it provided passages of e-mails in May to Mr. Baum from Mr. Dopp discussing the existence of police travel records of Mr. Bruno and suggesting a “new and different way to proceed re media.”

While the report did not allege a criminal wrongdoing, it was a devastating setback to a first-term governor who was elected last year on a mandate to restore integrity to a scandal-ridden capital.

Mr. Spitzer has sought to use the moral credibility he earned while attorney general as a crusader against white-collar crime to press lawmakers to approve new campaign finance and ethics rules and to make the case to voters for taking control of the Senate away from Republicans, whom Mr. Spitzer has accused of exhibiting the worst habits of Albany.

The report also appeared to vindicate Mr. Bruno, whose use of police escorts to travel to New York City to attend fund raisers were deemed proper because the majority leader conducted official state business during the trips. It also further the raised the profile of Mr. Cuomo, a Democrat who is emerging as a potential primary rival to Mr. Spitzer in the 2010 election.

Seeking to contain the damage, Mr. Spitzer said he endorsed the findings and insisted that he was unaware of the plot to discredit Mr. Bruno, with whom Mr. Spitzer has feuded since taking office.

Offering an apology to Mr. Bruno and the people of New York, the governor said he was misled by his staff and he immediately suspended Mr. Dopp and reassigned the other official. In an interview with reporters at his New York City headquarters, Mr. Spitzer said he took “full responsibility for the failures that occurred within my administration.”

“There were absolute improper judgment calls made and there is no excuse for that,” he said. “My administration I believe stands for — will continue to stand for — ethics, integrity, and we will be measured not only by the inevitable errors that are made but more importantly how we respond to those errors.”

With the governor in his most vulnerable position since taking office, Senate Republicans immediately began preparing a strategy to further harm his administration.

Mr. Spitzer said Mr. Baum did nothing inappropriate, and that he has “absolute confidence in his judgment and integrity.” He said he and Mr. Baum thought that administration officials were responding to a proper press inquiry and weren’t aware of the special actions undertaken by the police.

“I became aware of this discrepancy recently,” Mr. Spitzer said.

Senator George Winner, the Republican chairman of the committee on investigations and government operations, said Senate committees have a “very broad jurisdiction to make inquiries.”

“We don’t have to create a witch hunt, but I would like the committee to have a look at the underlying e-mails and transcripts to see if there is other stuff out there,” Mr. Winner said.

He said the committees could issue subpoenas if the documents are related to legislation under consideration by lawmakers, a hurdle that would easily be cleared if lawmakers introduce legislation, for instance, changing how freedom of information requests are handled by the state.

The report says Mr. Dopp and a top homeland security official, William Howard, a rare holdover from the Pataki administration, had insisted to police officials that they were responding to a Freedom of Information request from a newspaper. The request never existed, the report says, which points out that police began collecting records weeks before Albany’s Times Union newspaper asked for the information and ran an article about Mr. Bruno’s trips.

The findings say the acting superintendent of police, Preston Felton, cooperated with the administration by directing police to recreate and begin preserving detailed records of Mr. Bruno’s schedule, information that was later leaked to the Times Union late last month.

The report chastises Mr. Felton for cooperating with the administration, saying the information he supplied was clearly not required under freedom of information law and that he took no effort to ensure the records didn’t jeopardize Mr. Bruno’s security. Mr. Spitzer said he would consider disciplinary actions against Mr. Felton, whom Mr. Pataki appointed last year and was expected to become the first black superintendent of police.

Mr. Dopp, a former Associated Press reporter and press aide to Governor Cuomo, has been Mr. Spitzer’s top communications aide since the governor started his political career in 1999.

He speaks regularly with Mr. Spitzer, to whom he refers colloquially as “boss man,” and with Mr. Baum, a former Orange County legislator who has been the governor’s most senior adviser for more than eight years and managed his 2006 race.

A source close to Mr. Spitzer said it was highly unlikely that Mr. Dopp would resume working for the administration once his suspension ends.