The informer was Avishai Raviv, who has been at the centre of a web of conspiracy theories since his double-agent role was revealed two years ago. His friend was Yigal Amir, now serving a life sentence for murdering Rabin in November 1995.
In its report, now declassified, Judge Meir Shamgar's inquiry found that Amir had boasted frequently of his plan to harm the prime minister. But, rather than warn the security service, Raviv told Amir that a biblical law which prescribes the death penalty for Jews who endanger their own people applied to Rabin.
"It is astonishing", the commission says, "that in his reports on Yigal Amir, he did not mention, or so much as hint at, Amir's well-known expressions of his intention to injure the prime minister."
The report dismisses allegations of complicity by the Shin Bet in the Rabin assassination but is scathing about the way Raviv was handled in his nine years as an informer: "We are dealing with an agent whose behaviour was replete with provocation, who was not properly under the control of his handlers - who on occasion endorsed his involvement in extreme activities designed to increase his authenticity."
Raviv ignored warnings about these activities, which included beating up Palestinians, attacking a left-wing Israeli MP, conspiring to torch a building, smashing Arab house and car windows, and training and arming bully boys.
"The agent brought in a great deal of information," the report concludes, "but he also violated the law repeatedly in the knowledge that he was exempt from responsibility because of his official backing. His supervision by the Shin Bet was ineffectual, and in most cases they learned about what happened only after the event."
Politicians are now demanding that Raviv be charged with not acting to prevent the assassination. Some MPs want his Shin Bet controllers to be charged, too.
Raviv was recruited by the Shin Bet in 1987 when he was 20. He had already been active in Rabbi Meir Kahane's ultra-nationalist Kach movement. Why, then, did he agree to inform on his friends? Not for money. Rather he seems to have enjoyed the excitement. The Shin Bet men were his heroes. But he was fatally selective in which information he gave them. - Eric Silver, JerusalemReuse content