LOS ANGELES, Sept. 25 – A $1 million false arrest suit against the city of Los Angeles by William Etson Garretson, who was jailed for two days after the murders of actress Sharon Tate and four others Aug. 9, 1969, went to trial Tuesday in Superior Court.

Garretson, now 25, flew to Los Angeles from his home in Lancaster, Ohio, for the civil jury trial before Superior Judge Thomas C. Yager.

Robert Cohen, Garretson’s lawyer, said the young man, is now married and has been working for a glassware manufacturer in Ohio for the last five years.

Garretson was a caretaker living in a guesthouse at Miss Tate’s rented Cielo Drive estate when the pregnant actress and three of her houseguests — coffee heiress Abigail Folger, hair stylist Jay Sebring and Voityck Frokowski, one-time associate of Miss Tate’s film-producer husband, Roman Polanski — were slain. Steven Parent, 18, who had been visiting Garretson, also was shot to death.

Charles Manson, Susan Atkins, Patricia Krenwinkel, Leslie Van Houten and Charles Watson later were convicted of the murders and are serving life sentences.

Garretson was the only one still alive at the secluded Benedict Canyon estate when a maid summoned police. Officers kicked in his door and arrested him at gun-point about 9 a.m.

He was released two days later at 2 p.m. after police said no evidence was found to implicate him.

Garretson had been in his guest house room listening to his stereo when the shootings and stabbings occurred. He said he heard no shots or screams and knew nothing of the crimes until police woke him up.

His lawyers explained Garretson had said goodnight to Parent about 11:30 p.m. or midnight. Parent was found shot to death in his car on a driveway leading from the home.

The civil suit claims the city is liable for false arrest, false imprisonment, invasion of privacy and violation of Garretson’s constitutional rights.

Dep. City Atty. Thomas Hokinson said he will argue that the police officers had probable cause to take Garretson into custody. He also said that, tech-nically, Garretson’s incarceration and release are “deemed a detention only and not an arrest.”

Garretson announced plans to file the civil action a week after he was taken into custody.

He said police had handcuffed him and then led him to three of the five bodies at the estate.

He complained that jailers would not let him take a shower or brush his teeth and “they almost didn’t let me eat a meal once.” He said an apologetic detective read him his constitutional rights hours after he was booked on suspicion of murder.

Garretson said on the night of the murders he wrote letters and listened to rock music until dawn. He said he felt “a little bit frightened” when he tried to make a phone call to determine the time and found the phone dead. (Evidence presented at the Manson trial showed the killers had cut the phone lines to the houses.)

Then, Garretson related, he had dozed off to be awakened by the barking of Christopher, a weimaraner, one of the three dogs he was being paid $35 a week to care for, and the police at his door.

Questioned by newsmen at the time of Garretson’s arrest, a police spokesman explained: “He was taken into custody because he was on the premises where five people were murdered.”

Garretson had worked for Rudy Altabelli, who rented the estate to the Polanskis.

Another spin-off trial from the 1969 slayings was scheduled to begin today in the criminal courtroom of Superior Judge Earl C. Broady. That involves perjury indictments against Manson’s chief prosecutor, Vincent T. Bugliosi, and Miss Atkins’ defense attorney, Daye Shinn, who are charged with falsely denying under oath three times that they gave newsman William Farr information despite a gag order during the 1970 Manson murder trial.

Farr, who covered the Tate slayings and subsequent trials for The Herald-Examiner, is now a Times reporter. He served 46 days in jail and faces five more for contempt because he refused to identify his sources.

The reporter has been subpoenaed as a witness in both trials — to aid Garretson in verifying his arrest in the civil case, and for questioning about his receipt of information and his sources’ identity in the perjury trial.

By MYRNA OLIVER