The government's case against deposed Panamanian leader Manuel Antonio Noriega was thrown into further confusion last week when federal investigators, probing the leak of tapes of Noriega's Miami jail cell telephone calls, identified as their chief suspect one of the principal government witnesses against Noriega.

On Thursday five Federal Bureau of Investigation agents, acting with a federal warrant, searched the home of Jose Blandon, seizing documents, computer disks and a facsimile machine. On Friday, they searched his bank safety deposit box.

The warrant said the agents were seeking items "which are evidence of theft and conversion of U.S. government property." Earlier last week, officials involved in the case said Blandon was the leading suspect in their investigation of the leaked tapes.

But Blandon, a former Panamanian diplomat who provided prosecutors with much of the information used in indicting Noriega in 1988 on drug-related racketeering charges, emphatically denied being the source of the leak. He countercharged in an interview that elements of the U.S. government who do not want the Noriega trial to go forward leaked the tapes to Cable News Network.

"Somebody in the government was leaking them," he said. Throughout the Noriega investigation, there have been conflicting views in the U.S. government over the wisdom of bringing Noriega, an acknowledged asset of the U.S. intelligence community, to trial. Federal officials said last week that documents likely to be presented during the trial are potentially embarrassing to some government agencies.

The possible undermining of Blandon's credibility as a witness against Noriega could have severe repercussions for the case. The trial is scheduled to begin Jan. 28, more than a year after Noriega was arrested after U.S. forces invaded Panama.

At the same time, Blandon, whom the government acknowledges it asked to listen to a number of the Noriega tapes in its possession, said in the interview that they included several conversations between Noriega and his lawyers. Acknowledgement of the taping of another such conversation, broadcast by CNN, led defense lawyers to seek dismissal of the charges on grounds that the attorney-client privilege had been violated.

Blandon said he traveled to Drug Enforcement Administration (DEA) headquarters in Miami five times in May and June to assist agents in sifting through possible evidence against Noriega, including 22 tapes of Noriega telephone conversations. He said DEA agents were present at all times that he had access to the tapes, from which he made only written notes.

Blandon, who asked that the exact location of his residence in a southwestern state not be disclosed because he said he fears for his safety, said he was also requested to and provided a written summary of the tapes for use by Noriega prosecutor Michael P. Sullivan and other officials. He said that the summary included references to several calls between Noriega and the office of his Miami defense attorney, Frank Rubino.

In at least one of those calls, he said, Noriega proposed contacts between his lawyer and that of Luis del Cid, a former Noriega associate. This week, del Cid pleaded guilty to reduced drug charges and agreed to testify against Noriega.

The public saga of the Noriega tapes began Nov. 7, when CNN broadcast excerpts of Noriega's calls. On Nov. 9, despite a federal court order, the network broadcast a more extended version of a call between Noriega and his defense team, prompting a controversy about whether DEA agents and federal prosecutors got inside information about the Noriega's defense strategy.

The controversy ended up in the Supreme Court, which temporarily upheld the restraining order until the lower court reviewed the seven taped conversations in CNN's possession and determined there was only the one attorney-client call.

On Friday, prosecutors in Miami filed a motion with U.S. District Judge William Hoeveler that gave the government's version of the tape controversy. It acknowledged that procedures set up to screen agents and prosecutors from Noriega's conversations with his lawyers were not always followed.

The motion also confirms some of the details in the account provided by Blandon. It said, "At the end of June 1990, 22 tapes . . . were reviewed, under the direction and supervision of the DEA case agents, by a person assisting DEA. A written synopsis of these tapes were prepared by this reviewer."

One official involved in the case stressed that not every conversation between a defendant and his lawyer falls under the protection. Attorneys could not have expected privacy, he said, because they knew the line was monitored.

A spokeswoman for the U.S. attorney's office in Miami said Friday, "The prosecutors have not listened" to any of the Noriega tapes, but said "we're neither confirming or denying" that the prosecutors may have received Blandon's summary of the calls that he reviewed.

Blandon served as Panama's consul general in New York, before breaking with Noriega and becoming his chief public accuser, first during Senate hearings in 1988, and later before a Miami federal grand jury that relied upon his testimony in its indictment. Former assistant U.S. attorney Richard Gregorie, who drafted the indictment, said that Blandon was the key witness concerning allegations that Noriega met with Cuban leader Fidel Castro to settle a dispute between Noriega and the Medellin drug cartel. That meeting is cited in the indictment against Noriega.

By Blandon's account, during the 11 months since Noriega's arrest he has often been consulted by DEA agents and prosecutors to interpret the meaning of various documents and conversations.

In May, Blandon said, DEA agents asked him to come to Miami, to cull through thousands of documents seized in the invasion. Working off a master list, he said, he made notes about Noriega's finances and the names of possible witnesses against him.

In the end, however, he said the DEA agents were disappointed with evidence provided by the written material. "In all those thousands of documents, there is nothing that incriminates Noriega," Blandon said. At that point, he said, the case against Noriega was "not as strong" as the prosecutors would have liked.

Throughout this period, Noriega was spending dozens of hours each week making telephone calls to Panama and around the world from his cell at the Metropolitan Correctional Center in Miami, despite warnings that they were monitored. The government subpoened tapes of the calls as part of its investigation, and the Bureau of Prisons prepared cassettes of excerpts taken from its large reel-to-reel recorder.

A senior government official said DEA asked that the prison officials screen the calls for attorney-client conversations. According to their motion filed Friday, prosecutors "took steps" to ensure they would not "inadvertently obtain" calls between Noriega and his lawyers.

A March 6, 1990, memorandum from prosecutors to the DEA, referred to in the motion, said the tapes should be screened first by an "outside" DEA agent who was not part of the prosecution team in order to ensure there were no attorney-client conversations on the subpoenaed tapes.

But that process was less orderly than prosecutors expected, partly because of the Panamanian slang used by Noriega. "The tapes are in code and he is very difficult to understand," Blandon said.

The government acknowledged in its motion that the careful screening process was eventually disregarded, and said that in June, instead of the "outside" agent, a "person assisting DEA" reviewed the tapes "under the direction and supervision of the DEA case agents," an apparent reference to Blandon.

Blandon said he spent five full days listening to 22 tapes in a room at the DEA's Miami field office. "When I went to lunch, I left all my stuff open on the table," Blandon said, adding that he was "never left alone, never took anything."

As he worked, he said, he made detailed notes on a legal pad. Blandon said that after his initial review of the conversations, he used these notes to brief a large group of DEA agents. He said that during this first briefing he mentioned the conversations with lawyers, including the discussion with Rubino.

"I read my notes," Blandon said, during a "group meeting to discuss the tapes. I told them I had heard Noriega talking to his lawyer about del Cid."

He said, "In that meeting they told me about the problem with the lawyers."

Blandon said he was staying at the Embassy Suites Hotel near Miami International Airport, registered under an alias. On his final day in Miami, he said, he was visited by Sullivan, who asked for a briefing on the tapes. "I mentioned everything," Blandon said, including the del Cid conversation. "I discussed this with Sullivan." The prosecution spokeswoman declined Friday to respond to questions about Blandon's statements regarding prosecutors.

The following weekend, Blandon said, he returned to his home where he said he received a call from a DEA agent who said the agency "urgently" wanted a memorandum that distilled the content of the calls "because Sullivan was asking for that."

Blandon said he prepared a six-page, handwritten memo that began, "In general terms, through these telephone conversations Manuel Antonio Noriega keeps in contact with and imparts instructions to his people in Panama, the Dominican Republic, France, Spain, California, Costa Rica and his lawyers in the U.S."

At one point the memorandum said, "On tape 52 Noriega gives instructions to his lawyers to talk with the lawyers of Luis del Cid." At another point it said, "On tape 51 Noriega talks with his lawyers and coordinates his version for the U.S. communications media."

At a third point in the memo, Blandon reported that "In tape 43 Noriega asks that all the existing information on Jose Blandon" be prepared. Last night CNN carried comments from New York University law professor Stephen Gillers suggesting Blandon's access to Noriega's calls gave him an unusual "window in on the strategy of the defense when it comes" to attacking Blandon's testimony.

Blandon said he faxed this document to DEA's Miami office, addressed to the attention of DEA Special Agent Steve Grilli, on a machine that was seized Thursday from his home by FBI agents.

Shortly after sending the fax, Blandon said, a DEA agent called back with an English language translation of the memorandum. "The FBI told me yesterday that they have that memorandum, the memo that I sent to Mr. Grilli," Blandon said in the Friday interview.

In its motion, the government confirmed that the summary spoke of a call to Noriega's lawyer, but said a DEA agent decided it was not a privileged attorney-client conversation. "There was a reference in the synopsis to a conversation between Noriega and his attorney. A further check by a second outside DEA agent was then made in order to determine whether there were attorney-client conversations on the tape. In August this second outside DEA agent reported there were no privileged conversations between Noriega and his attorneys on the particular tape checked."

Last week Judge Hoeveler ordered release of transcripts of the seven taped conversations obtained by CNN; the transcripts were prepared by court personnel after CNN turned over the tapes under a court order.

The transcripts contain several references to "overlapping conversations" and informed sources familiar with the FBI investigation say it is this background conversation that has pointed to Blandon.

In the warrant used to search Blandon's house Thursday, the government said it sought "notes, papers, documents . . . and memoranda regarding" telephone conversations involving Noriega, financial information regarding Noriega and his associates, telephone numbers of people contacted by Blandon regarding Noriega and facsimile transmission equipment.

Staff writers Laura Parker in Miami, Michael Isikoff in Washington and Joe Pichirallo in Los Angeles contributed to this report.