'Missing' Israeli scientist was jailed as spy: The hunt for a chemical warfare expert has ended with an official admission, writes Peter Pringle

ONE of the more elusive spy mysteries of the Cold War started to unravel yesterday when Israel officially acknowledged that one of its top chemical and biological warfare scientists had been arrested 10 years ago and had not innocently 'disappeared in Europe', as the Israeli authorities had previously claimed.

For the first time, the Israeli censor allowed newspapers in Jerusalem and Tel Aviv to publish accounts of the arrest of Marcus Klingberg, the former deputy director of Israel's Institute for Biological Research. Now the world can infer that Klingberg, a former Red Army colonel, was a spy, but exactly what secrets he divulged and whether he worked alone or was part of a Soviet spy ring is still not clear.

Until yesterday, Israel had steadfastly maintained that Klingberg, who worked at the top-secret chemical and biological research station at Ness-Ziona, 15 miles from Tel Aviv, had suffered from mental illness and had disappeared while attending a scientific conference in Switzerland. In fact, he was arrested in 1983 and sentenced in secret to 18 years in jail by a Tel Aviv court.

Since then, each time journalists have tried to investigate Klingberg's alleged disappearance, they have been blocked by the Israeli authorities. The Tel Aviv evening newspaper Ma'ariv, which first mentioned he had disappeared in October 1983, six months after he was arrested, tried to publish a 4,000-word article in 1988 but was stopped by the censor.

During my own inquiries, then for the Observer, into Klingberg's whereabouts my car was broken into and documents about the scientist were stolen.

In 1988, the New York Hebrew-language weekly newspaper Israel Shelanu reported that Klingberg had been arrested and was part of a possible three-cornered spy swap between Israel, the US and the Soviet Union. The Israelis were apparently telling Washington that Moscow was willing to pay a 'very high price' for Klingberg.

If any swap took place, it evidently did not involve Klingberg - who is now 75 and in ill-health - according to Israeli newspapers.

The key question now for the Cold War espionage record is what secrets Klingberg divulged, and whether they were Israeli-only secrets or compromised Western security in a wider context by giving away military intelligence common to the Western alliance. Being a key member of the alliance, Israel had access to many Nato secrets.

At the time of his disappearance, Klingberg held a teaching post in epidemiology at Tel Aviv University, as well as being deputy director of the Ness-Ziona institute. Inside the institute's 10ft-high walls topped with barbed wire, Israel conducts defensive research into chemical and biological warfare.

I stumbled across Klinberg's name by accident in the summer of 1985 while investigating Reagan administration charges that the Soviet Union had used a poison produced by fungi, known as mycotoxins, as a chemical warfare agent in Southeast Asia. (The claims have since been refuted by US and British scientists).

Before emigrating to Israel in 1948, Klingberg was a colonel in the Red Army during the Second World War and was assigned to the Orenberg district in which there was a devastating epidemic of mycotoxin poisoning. Mycotoxins grow on mouldy grain and thousands of hungry Russian peasants died in the epidemic.

In the autumn of 1985 I went to Israel to try to interview Klingberg, thinking he might have knowledge of a Russian defence programme to use mycotoxins as a weapon. Each time I mentioned his name to his Israeli colleagues they said his disappearance was 'hush-hush', but they did not believe the official explanation that he had fallen ill in Switzerland and disappeared.

Klingberg's wife, Wanda, who has since died, told me in her Tel Aviv apartment that she knew where he was but could not talk about it. I wondered at the time if Klingberg had defected to Russia.

At one point during my inquiries, I took time off to visit the crusader castle at Ashkalon. My car was broken into and my briefcase, containing papers about Klingberg and my passport, was stolen. I informed the local Israeli police, who were most helpful and seemed to agree with me that, most probably, the thief had been preying on tourists.

A few months later, the police returned the briefcase and my passport, but some papers and photocopies of newspaper articles from Tel Aviv archives were missing. The more I learn about the case, the more I wonder if the thief had been working alone.