Thomas A. Twetton, recently named as the Central Intelligence Agency's deputy director for operations, was deeply involved in the secret arms-for-hostages dealing with Iran, according to testimony before the congressional Iran-contra committees and former CIA officials.

Twetton, who in 1985 and 1986 was deputy and then chief of covert activities for the CIA's Near East division, dealt regularly with former White House aide Oliver L. North as the agency "case officer," handling the logistics and funds for the initial transfer of U.S. arms to Iran.

Twetton's 1987 testimony before congressional Iran-contra investigators was released to the public in 1988, but his name was deleted from the published version because he held a covert operations position. He was identified only by the abbreviation "C/NE," representing his job at the time as chief of the Near East division.

In his testimony Twetton outlined how he:

Worked to try to prevent then-CIA director William J. Casey from getting involved in an arms-for-hostages scheme using Iranian middleman Manucher Ghorbanifar in the summer of 1985.

Informed North in September 1985 of Ghorbanifar's questionable record in CIA's files.

At North's direction, set up with the Pentagon in January 1986 the first shipments of U.S. TOW anti-tank missiles that were to gain release of U.S. hostages held in Beirut.

Carried North's message to the Defense Department that the price for each weapon should come down from $6,000 to $3,000 apiece.

Was with North and others when they met with Iranian middlemen in February 1986 in Frankfurt, March 1986 in Paris and April 1986 in Washington.

Briefed former White House national security adviser Robert C. McFarlane prior to McFarlane's secret trip to Tehran in May 1986.

Knew of the overlap that North created by using retired Maj. Gen. Richard V. Secord and businessman Albert Hakim in both the Iran arms sales and aid to the Nicaraguan rebels in Central America.

Twetton testified that although he was aware that excess money was being generated by the arms sales, "it never occurred to me . . . that North was raking it off {for the contras}. That was beyond the pale."

Twetton's promotion, announced last month and effective Jan. 1, is not subject to Senate approval.

Robert M. Gates, who was Casey's deputy at the CIA for most of the Iran-contra affair, failed to get Senate approval to be Casey's successor, but was named by Bush as deputy national security adviser in the White House.

A handful of other CIA officials, linked to questioned contra activities, took early retirement or were penalized with reprimands or forced retirement when William H. Webster took over as CIA director.

Twetton's Iran-contra committee testimony includes several instances where he could not recall events that are still subject to dispute.

He could not, for example, remember a memo written by a CIA colleague in March 1986 that described how Ghorbanifar told North that the Iranian arms sales could be used in Central America for the Nicaraguan rebels.

"Well," Twetton said upon being shown the memo, "I don't know whether I saw that or not. If I had, I assure you that I would have regarded it like everything else that Ghorbanifar said."

Twetton also testified that he never tried to find out what caused the wide difference in the price charged the Iranians, about $20.5 million for weapons that had cost the CIA $6.5 million.

In the CIA announcement of Twetton's appointment, Webster said he was "very pleased that Tom has accepted this appointment. He has a very distinguished record of service, and I'm fully confident that he will do an outstanding job in leading the operations directorate."