JERUSALEM: The man considered the Soviet Union’s most successful spy in Israel before being unmasked more than 30 years ago has died in Paris at the age of 97, his daughter said on Tuesday.

Marcus Klingberg was sentenced to 20 years in prison in 1983 for having passed information to Moscow on Israeli biological weapons research.

He had worked as deputy head of the Israeli Institute for Biological Research and managed to avoid detection for years before finally being found out with the help of a double agent.

His case was so sensitive that his arrest, trial and conviction were kept secret for more than a decade afterward.

“He was a Communist who acted out of conviction and gratitude to the Red Army (of the former Soviet Union) for having allowed him to fight the Nazis who massacred his entire family in Poland (during World War II),” daughter Sylvia Klingberg said.

Klingberg had always maintained that his motivation for spying was ideological and not financial.

Born in Warsaw into an ultra-Orthodox Jewish family, Klingberg fled Poland during the Nazi invasion in 1939 and made his way to the Soviet Union, where he studied medicine.

Published in Dawn, December 2nd, 2015