The violence deep in a South American jungle that ended Saturday with the slaughter of hundreds was not an isolated event, but the bloody climax to a history of threats and terror swirling around the Peoples Temple and its charismatic leader, the Rev. Jim Jones.

The regilious group's tactics of persuasion ranged from mass letter-writing campaigns and anonymous, late-night telephone calls to reporters and editors warning of unspecified consequences that would follow unwanted publicity, to ritual beatings of members and goon squads dispatched to harrass any who sought to leave the fold.

But what began with a few letters to San Francisco publications, and other tactics of intimidation, ended with apparent mass suicide-murders in the Guyanese jungle and an FBI investigation ito a reported Peoples Templa pla to kidnap high U.S. government officials in case Jones was arrested in Guyana.

The alleged kidnap plot, revealed to FBI agents Sunday by a number of current and former temple members, apparently was a contingency plan that was never implemented.

"The allegations are not garbage," Charles R. McKinnon, special agent in charge of San Francisco's FBI office, said when asked what credibility he gave the reports. "The information we have is reliable. Whether we'll be able to prove it in court is another matter."

Such threats to his constituents led Rep. Leo Ryan, (D-Calif) a 53 year old California Democrae, to travel to the Peoples Temple jungle agricultural settlement in Gauyana to investigate whether Americans were being heft against their will. Ryan himself had been threatened.

In fact, the congressman, who was killed for his search, received a telegram from Gualana that was "openly hostile" to visit, said Dan Cook, a congressional investigator and cloe personal friend of Ryan's but an unfriendly letter from Peoples Temple Attorney Mary Lane prior to the warning of trip. Ryan went anyway.

"He knew he would not be welcome with open arms, but he certainly didn't expect such a senseless thing as this," Cook said.

Jones, a flamboyant leader who often harped on fears of harrassment of his church by unnamed enemies, went so far as to arrange phony assassination attempts on his own life, say cult members. A speech by Jones would be interrupted by the crack of gunfire and he would announce that people were trying to kill him.

"Paranoid" is the term some former members use to describe the man who use ritual spankings and "boxing matchess to discipline followers. Reports reached the United States of an elderly woman being knocked unconscious at one such session in the jungle commune. Jones also exhorted cult members to spy on one another, former members claim.

It was the practice of the 46 year old leader to pay visits to would-be critics with his attorney, a public relations man and a large, imposing squad of bodyguards.They would be wearing dark-blue suits and sunglasses.

It was just such a "goon squad" that visited th e offices of New West magazine as it was preparing an article critical of Jones and Peoples Temple for publication in August 1977.

"They threatened us with libel suits if we printed the story," said New West executive editor Rosalie Wright in a telephone interview yesterday. The article described faked faith healings by Jones, members being forced to turn over their property to the church, ritual beatings, shady financial maneuverings and a creed that required total obedience to Jones.

Former members of the cult were quoted in the article as saying that members had been intimidated into signing powers of attorney to Peoples Temple and signing false confessions to such crimes as child molestation, as ways of preventing them from defecting.

No suit was filed against the magazine by the cult, but Wright said she received midnight phone calls warning her not to publish the article.

Members of the cult were exhorted to deluge New West and other publications critical of their leader with hundreds of letters. Before the article appeared, calls jammed New West switchboards in San Francisco and Los Angeles, said Wright, who moved from her house and sent her children into hiding.

Such tactics had succeeded in having the article killed by a former editor, and had intimidated San Francisco Chronicle reporter Julie Smith to the point that she turned her profile of Jones into "a goddamn valentine," she says.

"It was so distressing," Smith said at the time. "Just this vast thing coming at you. All the letters, all the phone calls, all this murmuring from people in high places. What happened in my case was that I ended up being completely ineffectual."

Under prodding from Jones, businessmen, civil leaders and politicians weighed in to emphasize the free meals and community programs that the Peoples Temple brought into the largely black Fillmore District. It was an impressive show of force.

Letters urging another look at Jones poured into the San Francisco Examiner after the newspaper published an article delving into Jones' activities, and the paper received threats of demonstrations by members of the cult. The life of the paper's editior and publisher, Reg Murphy, who had been kidnaped several years ago and held for $700,000 ransom by a right-wing terrorist, was threatened again yesterday, said a source close to the paper. The threat was believed to be from someone connected with Jones' group.

Mysterious visitors, assaults in her home and threats against her family have also haunted free-lance reporter Kathy Hunter of Ukiah, Calif., since she returned from a futile attempt to interview Jones in Guyana.

Her trip last May turned into a nightmare when fires broke out in adjoining rooms of her quarters. Upon returning home, she was confronted by three men in her living room and warned not to write anything more about Peoples Temple.