he only criminal trial which will ever attempt to account for the more than 900 murders and suicides at the Jonestown massacre in 1978 ended today in a mistrial after jurors who had deliberated over eight days admitted they could not reach a verdict.

Jury foreman Godfrey Powers, a retired bank executive, told U.S. District Court Judge Robert F. Peckham that the seven men and five women were deadlocked on all four charges against Larry Layton, a 35-year-old X-ray technician described by prosecutors as an "inside man" in the jungle attack on Rep. Leo J. Ryan (D-Calif.) and several others.

Peckham, who had asked the jurors to try one more time when they told him they were deadlocked Friday, granted a defense motion for a mistrial. Federal prosecutors indicated they wanted to retry Layton, but have said they must await instructions from Washington.

Layton, a short, dark-haired man who has sat virtually expressionless throughout the trial, smiled broadly when the jury first confessed it was deadlocked but betrayed no emotion when the trial ended today. Each juror told Peckham in turn he or she could not decide on any of the four charges, which included conspiracy in and aiding and abetting the murder of Ryan and the wounding of U.S. deputy chief of mission in Guyana Richard Dwyer.

The jurors, who declined to be interviewed, appear to have entangled themselves in the intricacies of the case, in which the government tried to implicate Layton in the attack on Ryan and Dwyer even though he never fired a shot at either man.

When Ryan was about to leave an airstrip near Jonestown, the Guyanan encampment of cult leader Jim Jones, and take several Jonestown defectors with him, a number of Jones' followers killed Ryan and four others and wounded Dwyer. Layton, pretending to be a defector, was inside a small airplane, where he allegedly shot and wounded two Jonestown defectors before being disarmed.

The federal prosecutors attempted to prove that Layton was operating under Jones' orders to shoot to kill the people in the smaller plane so that the larger group could concentrate their attack on Ryan's party.

That would have made Layton part of the conspiracy, but testimony at the trial from Ryan aides indicated that Layton had set out on his mission unaware of the plan to shoot Ryan.

Layton was acquitted by a jury in Guyana of the shooting of the two defectors after one of the wounded declined to testify and the other refused to swear on the Bible. And federal officials here could charge him only with a crime against Ryan and Dwyer, who as federal officials were the only victims protected abroad by U.S. law.

Also killed that day were San Francisco Examiner photographer Greg Robinson, NBC reporter Don Harris, NBC cameraman Robert Brown and Jonestown defector Patricia Parks.

More than 900 Jonestown followers, apparently including those who actually shot Ryan, died by drinking a fruit drink laced with poison, at Jones' urging later that day. The cult leader died too, of a gunshot wound.

Prosecutors have indicated they may eventually give up on a retrial if they fail again to get permission to play what they consider key evidence, a tape recording in which Jones refers to Layton as his man sent out to stop the Ryan party from leaving.

Layton remained loyal to him to the end and is said by his attorney to be satisfied with prison life as a way to expiate his "frustrated martyrdom and remorse." Attorney Tony Tamburello said "I think I want an acquittal more than Larry does."

Besides the Layton trial, the events of Nov. 18, 1978, have produced hundreds of lawsuits and claims against the Peoples Temple, the State Department and even Ryan's estate, criss-crossing each other like a spider's web.

Ryan's children have sued the State Department, contending it failed to warn the congressman of the dangers he faced at Jonestown. Eight Jonestown defectors and relatives of defectors, including some wounded at Port Kaituma airstrip, are suing Ryan's estate (valued at only $36,000), charging the congressman failed to give them promised protection in their escape.

Nearly everyone involved, including Layton, is pursuing a claim against the estate of the Peoples Temple, a total of about $1.8 billion so far. No one will receive anywhere near that amount, for the estate is now valued at only about $8 million in property, income and other goods turned over or willed to Jones' organization by his followers.

The court-appointed receiver, former Bank of America general counsel Robert Fabian, recently paid the federal government $1.7 million for the cost of transporting the bodies home from Guyana. The government had wanted $4.3 million.

Fabian rejected, with what San Mateo County Assistant District Attorney L. M. Summey called "a great deal of derision," that county's claim for $300,000 to pay the cost of the special election needed to fill Ryan's congressional seat.

As the claims, many not scheduled to be heard until next year, drag on, the estate grows by about $100,000 a month in interest. About half of that has been going for fees to Fabian and other attorneys working with him on the complex case, a drain which annoys many claimants' attorneys.

"It's set up under the usual system," said Robert Bockelman of San Francisco, who is representing several defectors and their families, "but the receiver has done some things which have caused conflicts and disputes, and meant more attorney's fees."

Jonestown followers defrauded of their property by Jones were ruled out as claimants, Bockelman said. The receiver also turned down a request to allow the taking of depositions now while several witnesses are in town for the Layton trial.

Fabian has traveled throughout Central America gathering up Jones' bank accounts and acknowledges the case has "many unique features." But he said he does not concern himself with "the imponderables" of life and death attached to the case.

He has settled about 400 claims already for $8 million in receivers certificates. At the end of the process they will probably yield only 50 or 60 percent of their value as the estate is divided on a pro-rated basis.

Louis Fazzi, a Claremont, Calif., attorney, on behalf of the widow of NBC cameraman Brown and a teen-age Vietnamese girl the Browns have been supporting, rejected a settlement offer of about $32,000. "Bob was at a point where his career is just taking off, and this is all they offer," Fazzi said.

Fazzi also has sued the U.S. government on the theory that the State Department, and particularly the Central Intelligence Agency, failed to share with Ryan's party all that was known about Jonestown.

The CIA connection still draws great interest from many participants in the Jonestown cases, including Layton attorney Tamburello. "We got some information from the CIA and everything was blacked out but the page numbers," he said.

Former Ryan aide Joe Holsinger and Peoples Temple defector Jim Cobb have suggested that Jonestown was in part a CIA behavior modification experiment and a device by which the agency manipulated the Guyanan administration of Prime Minister Forbes Burnham.

Most of the hundreds of survivors of the tragedy seem intent now, however, on putting the matter aside.

Jackie Speier, a Ryan aide who was severely wounded in the shooting, failed to win election to Ryan's seat but has since won a place on the San Mateo County Board of Supervisors. "I thought I put this aside years ago," she said, adding she was not even sure how much her lawyers were attempting to claim from the Jonestown estate.