US authorities rejected that claim but cannot appeal the decision.
US authorities were unable to agree on a process for testing rival drugs.
The decision came as a blow to the US authorities who thought they may finally bring him to trial after 32 years.
We have a right to ask questions and demand answers from the US authorities.
US authorities have put in place enhanced measures to monitor potential outbreaks.
US authorities claim the cost of tracking and correcting the problems he caused was over $700,000.
The suspect was later arrested by US authorities in 2002.
Another $400m (£257m) would be paid in penalties to the US authorities.
If this does not happen, we have to immediately stop delivering any kind of information to the US authorities.
US authorities eventually released him after more than a year's captivity, deciding he had no intelligence value.
