WASHINGTON — Major problems in developing criminal cases against U.S. participants in the Iran- contra scandal are being created by Israel's refusal to let investigators for independent counsel Lawrence E. Walsh question Israeli agents directly involved in the affair, sources close to the probe said Tuesday.
The alleged "stonewalling," as one source characterized it, has become a significant impediment because alternative sources of information on key aspects of the investigation--former National Security Adviser John M. Poindexter and fired White House aide Oliver L. North--have refused to testify, invoking their right against self-incrimination.
The information Walsh is seeking from the Israelis ranges from who originated the Iranian arms sales to how Swiss bank accounts were used to channel profits to Nicaragua's rebels.
Sources said that the Israeli stance would hamper the investigation of such officials as Poindexter, who resigned last November when it was revealed that profits from the sale of arms to Iran had been diverted to the Nicaraguan rebels, and North, who was fired as a National Security Council aide at the same time.
Described as Intransigent
One U.S. official described Israel's stance as more intransigent in the Iran-contra probe than it was in the investigation of Jonathan Jay Pollard, the American sentenced last week to life in prison because of his spying for Israel.
Walsh and a State Department spokesman declined comment on the reported impasse. But sources elsewhere in government said that the independent counsel still hopes to persuade Israel to permit the interviews.
In Israel, a senior government official said that his country has nothing to apologize for in the Iran-contra affair--unlike the Pollard case--and predicted that Israel will not back down on refusing to let its citizens be questioned directly.
Insists on Restrictions
Instead, Israel is insisting on written interrogatories, a technique that U.S. investigators said lacks the flexibility and responsiveness needed to unravel facts in a complex criminal probe.
Israel placed the same restriction on investigators from the congressional committees investigating the Iran-contra affair, but leaders of those investigations expressed no dissatisfaction with that arrangement.
The presidentially appointed panel headed by former Sen. John Tower (R-Tex.) that issued its report on the scandal Feb. 27 also could not directly question Israeli principals. "Without the benefit of the views of the Israeli officials involved," the commission concluded, it was "hard to know the facts" about the Israeli role in initiating and prolonging the arms sales to Iran.
A spokesman for the Israeli Embassy here cited Prime Minister Yitzhak Shamir's agreement last month with House and Senate committees during his visit to Washington to supply full answers to written questions "as detailed as they want." Shamir also promised President Reagan that Israel would cooperate with the investigations of Walsh and the Tower Commission.
The spokesman, Yossi Gal, said that Israel "will cooperate fully with all the investigative bodies--on a government-to-government basis." That precludes direct questioning of individuals.
The senior government official in Israel criticized Walsh's investigators as "less experienced" than their counterparts on the Tower Commission and the Senate and House committees. It was not clear whether the official was referring to FBI agents assigned to Walsh or the 20 associate counsels in his office.
Would Question Several Men
Among the Israelis whom U.S. investigators seek to question is Amiram Nir, a counterterrorism adviser to former Israeli Prime Minister Shimon Peres who allegedly took part in arranging the arms sales to Iran. Walsh's investigators also want to question David Kimche, Al Schwimmer and Yaacov Nimrodi.
Kimche was director general of the Israeli Foreign Ministry in July, 1985, when he met on the approach to Iran with Robert C. McFarlane, then Reagan's national security adviser, according to the Tower Commission. Schwimmer and Nimrodi are private Israeli arms dealers who helped broker the arms deals, the commission said.
Sen. Daniel K. Inouye (D-Hawaii) and Rep. Lee H. Hamilton (D-Ind.), chairmen of the Senate and House committees investigating the Iran-contra case, have said that they were satisfied with Israel's pledge to provide written answers to questions jointly submitted by their panels.
Calls Cooperation 'Excellent'
Sen. Warren B. Rudman (R-N.H.), vice chairman of the Senate committee, recently described cooperation from the Israelis as "excellent" and said that he understood their unwillingness to allow their citizens to be questioned in person.
"They say that as a sovereign nation they do not believe that the legislative body of the United States ought to be dealing directly with their agents and I can understand that," Rudman said. "I don't like it, but I can understand it."
Sources familiar with the matter noted that Walsh and his investigators face a different mission from the congressional panels--one of deciding whether evidence supports seeking a grand jury indictment and building a case with evidence beyond a reasonable doubt to convince a trial jury.
Ronald J. Ostrow reported from Washington and Dan Fisher reported from Jerusalem.