LOS ANGELES (AP) _ The first prosecutor in the ''Twilight Zone'' manslaughter case has filed a $10 million claim against the district attorney's office, alleging he was harassed by a campaign to destroy his reputation, an official confirmed Wednesday.

Deputy County Counsel Ray Fortner said the claim by Gary Kesselman was filed in June and ''it's in the investigative stage.''

''We've had preliminary contacts with the district attorney's office,'' he said, but noted that there had been no formal action on the claim.

Such a claim is considered preliminary to filing of an actual lawsuit.

Kesselman and his lawyer did not immediately return telephone calls seeking comment about the matter Wednesday.

The ''Twilight Zone'' case became a Hollywood cause celebre when director John Landis and four associates were charged with involuntary manslaughter in the 1982 movie set deaths of actor Vic Morrow and two children. After an acrimonious 10-month trial, they were acquitted May 29.

Kesselman, who guided the case through a preliminary hearing, stepped out before the trial. He was replaced by Deputy District Attorney Lea Purwin D'Agostino, who called Kesselman to the stand to support the disputed testimony of a key witness.

Kesselman, however, wound up contradicting the witness and dealing a severe blow to the prosecution.

In angry confrontations outside the jury's presence, Kesselman contended that Mrs. D'Agostino pressured him to perjure himself under oath; she vehemently denied this.

Kesselman's claim against his employer suggests that when he failed to support Mrs. D'Agostino's case, the district attorney's office set out to harass him and destroy his reputation and credibility.

Mrs. D'Agostino declined comment Wednesday.

Also named in the claim were Chief Deputy District Attorney Gilbert Garcetti and Deputy District Attorney Richard Hecht, a key member of the district attorney's staff.

The county counsel's office said details of the claim were considered confidential and the claim itself was not a public record.

During the trial, production secretary Donna Schuman quoted Landis as suggesting before the accident that he could go to jail for using the children illegally in the explosive scene.

Kesselman differed with Mrs. Schuman on whether she had told him about the statements.

The first testimony jurors asked to hear again as they deliberated the case was that of Mrs. Schuman and Kesselman.