LOS ANGELES (AP) _ The husband of a key witness in the ''Twilight Zone'' manslaughter trial supported her testimony from the stand after the judge rejected defense bids for dismissal and ordered the trial back on track.

The appearance of Dr. Harold Schuman marked the resumption of testimony after weeks of battles between defense and prosecution attorneys over the testimony of Schuman's wife, Donna, a production secretary.

In a rancorous session outside jurors' presence Monday, defense attorney Harland Braun denounced the prosecutor, Deputy District Attorney Lea Purwin D'Agostino, as ''a liar'' and demanded an investigation of alleged prosecutorial misconduct.

Superior Court Judge Roger Boren refused to become embroiled in the debate.

''I feel going into any of these areas is a waste of the court's resources and the case ought to go forward now,'' Boren said.

Director John Landis and four colleagues - associate producer George Folsey, production manager Dan Allingham, special effects coordinator Paul Stewart and pilot Dorcey Wingo - are charged with involuntary manslaughter in the July 23, 1982, helicopter crash deaths of actor Vic Morrow, 53, and two children, Myca Le, 6, and Renee Chen, 7. They were killed during filming of a war scene for ''Twilight Zone: The Movie.''

Mrs. Shuman testified that Landis and associate producer George Folsey spoke of the possibility of going to jail, before the accident, for using children in the scene.

She said she reported that to the former prosecutor in the case, Gary Kesselman, and said he told her he would withhold it until the trial to gain an advantage over the defense. Her husband backed up her statements.

Kesselman has contradicted Mrs. Schuman's account under oath, but jurors were not present for his testimony.

When testimony resumed Monday, jurors heard first from a friend of the Schumans', Gail S. Wellens, who said she remembered Mrs. Schuman relating a statement from Folsey regarding the chance of jail terms for the filmmakers for employing children in the film.

''Did she tell you Mr. Folsey was joking?'' asked attorney James Sanders.

''Oh no,'' said Ms. Wellens. ''In fact, it was one of the grimmest luncheons I've ever attended.''

Schuman, a psychiatrist who helped recruit the two children for the film, testified that Folsey personally assured him the children hired for the film wouldn't be in danger.

''He said there would be special effects explosives but he was very reassuring that they would not be near the children ...'' he recalled.

Earlier, Braun threatened to seek the prosecution of Mrs. D'Agostino on the grounds of perjury and suborning of perjury.

He said he believed Mrs. D'Agostino backed up critical testimony by Mrs. Schuman, even though ''Mrs. Schuman made up the story on the witness stand.''

Mrs. D'Agostino said of the allegation, ''I don't think it merits discussion.''