The Rev. Mr. Fisk died almost instantly from a bullet fired by a man who interrupted the churchman as he stood conducting a special class in the downtown headquarters of the Church of Scientology of Washington State, 1112½-Fourth Avenue.

A SINGLE SHOT, fired from a .380 automatic, cut short the Rev. Mr. Fisk's pleas to summon a police officer.

"This man is going to shoot me . . . go get a cop." Fisk, who is known in his religion as an auditor, said, as soon as the man appeared in the building, "Please, someone get a cop," he urged again.

BEFORE the startled congregation members could obey, the man casually pulled a gun from his pocket, loaded it with a clip from another pocket and then fired.

The Rev. Mr. Fisk turned as the gunman pulled the trigger, the bullet entering the chest just below the right armpit. He fell without a word. The gunman calmly walked out the front door.

The Rev. Mr. Fisk was pronounced dead on arrival at King County Hospital a few minutes after the shooting, which occurred just before 9:30 p.m.

LITTLE MORE than an hour later, a man identified as Russell Edward Johnson, 36, of 3832 NE 91st Street, a carpenter and building contractor, surrendered at police headquarters with an attorney. He was booked without charge in City Jail. Detectives said they has been looking for Johnson since a few minutes after the slaying.

On the advice of counsel, Johnson declined to give officers a statement. However, as he entered headquarters, he asked:

"Is the guy dead?"

POLICE, delving into the shooting, said the Rev. Mr. Fisk was described as an ordained minister in the Church of Scientology, which is a little know but worldwide organization. It has extensive offices in Los Angeles, Washington D.C. as well as Seattle. The home church is thought to be in England.

The Rev, Mr. Fisk's wife, Donna, is believed to be in England. The couple lived at an apartment at 1022 Union Street but neighbors there said they had not lived there for the past two or three months.

A PAMPHLET, found by police at the scene of the slaying, described the religion as: "Scientology is the study of the Human Spirit in its relationship to the Physical Universe and its Living Forms."

It was not ascertained immediately if the Rev. Mr. Fisk was an ordained minister in the usual sense or if he was a graduate of a recognized school of theology.

ACCORDING to witnesses, four of whom identified Johnson as The Rev. Fisk's assailant, the Scientologist was conducting a class in dianetics, one phase of the religion, at the group's headquarters. The Rev. Fisk apparently had no notion that Johnson would be at the meeting.

Johnson was described by other church members as either a follower or former follower of the Rev. Mr. Fisk. One witness said Johnson at one time was one of Fisk's leading pupils.

Joseph G. Terabasso, 26, of 5011-2nd Ave. NW, attending the church for the first time, said he and three others were with the Rev. Mr. Fisk when Johnson entered.

"We were all dumbfounded when Fisk said, "Please someone get a cop." Terabasso recounted. The shot was fired as Terabasso and others attempted to flee the room.

POLICE were at a loss to learn the motive for the fatal shooting but detectives said they were investigating several possibilities. None of the witnesses could give any reason for the slaying.