The film editor for the CBS documentary at issue in retired general William C. Westmoreland's $120 million libel suit said today that he had warned CBS producer George Crile before the broadcast that Crile was jeopardizing the project and "destroying the credibility of the film."

Ira Klein, Westmoreland's final witness as the trial entered its 13th week, also said that Crile and others at the network refused to heed his warnings about flaws he believed were developing in the show, which was aired Jan. 23, 1982.

Klein testified that one CBS official said "don't get involved" when Klein complained that Crile's thesis for the show, entitled "The Uncounted Enemy: A Vietnam Deception," was not supported by the transcripts of interviews conducted for the documentary. Klein also said he was rebuffed when he told Crile that the film's credibility would be strained "by not permitting Gen. Westmoreland to have time to present his point of view."

"Did Mr. Crile say anything in response to that?" Westmoreland lawyer Dan M. Burt asked.

"Yes," Klein said. "Mr. Crile told me he was deciding what was accurate and what was true and what wasn't."

In cross-examination, CBS attorney David Boies tried to attack Klein's credibility by demonstrating that the two men had a personality conflict, citing an interview Klein gave after the broadcast.

Klein acknowledged that he had told author Don Kowet that Crile was "a social pervert," and said that by the end of their working relationship on the show, "I couldn't stand to look at him."

"Did you tell this reporter that Mr. Crile was 'devious and slimy?' " Boies asked at one point.

"Yes," Klein said firmly, "and I believe that to be so."

Boies also attempted to prove to the jury that Klein was merely a technician, who was not familiar with many of the documents that the "CBS Reports" team used in preparing the show.

The program alleged that Westmoreland participated in a "conspiracy" of top military intelligence officials in 1967 to suppress higher enemy troop figures to maintain support for the Vietnam war.

Klein made it clear that he believed that many of Crile's methods were unethical and not up to CBS' journalistic standards.

A free-lance employe for CBS from 1978 to 1982, Klein had his strongest moment on the stand when he described his role as a sound technician during a screening of the show for Van Gordon Sauter, new president of CBS News.

At the screening, Klein testified, Crile wanted to cut short a statement that Westmoreland made on an NBC "Meet the Press" program in 1967 because the end of the quotation seemed to contradict what Westmoreland had said in his interview with Mike Wallace.

Klein, who was working the sound system for the screening, testified that Crile had told him that he would signal the moment to cut off the statement by standing up in the back of the room and signaling with a downward motion of his hand.

"And did he do that?" Westmoreland lawyer Burt asked.

"Yes, he did," Klein said.

Klein, who is now working as a free-lance film editor for the Corporation for Entertainment and Learning, an independent television production firm, said that Samuel Adams, a former Central Intelligence Agency analyst who is a co-defendant, had told him that Westmoreland's intelligence chief for part of the period in question was "healthy as a clam," and not seriously ill, as Adams and Crile had previously believed. After one session with Crile and Adams, Klein said he told Crile, "You realize that Mr. Adams seems obsessed." Klein testified that Crile had said he knew that and later told Klein not to allow Adams in the film editing room.

Klein also testified that after the broadcast had aired, Adams came into his editing room "and told me that we have to come clean, we have to make a statement, the premise of the show is inaccurate."

"I looked at Sam and said, 'It's a little bit late,' and Mr. Adams said to me that he was telling George Crile all along that LBJ President Lyndon B. Johnson had to know."

Speaking with reporters outside the courtroom, Adams denied that he had said "exactly that" to Klein, but he said Klein's testimony was "probably an extrapolation of my view that probably somebody higher up" than Westmoreland knew about the suppressed intelligence figures. "But we didn't have the goods on anybody else."

CBS will begin presenting its case on Tuesday.