Britain's yearlong case against nine North Africans accused of plotting to spread the deadly toxin ricin (search) in the English capital resulted in only one conviction — an Algerian linked to Al Qaeda (search) — with eight others either not brought to trial or acquitted, according to court documents released Wednesday.

Britain had forbidden reporting on the case until all trials were complete, and a judged lifted the prohibition after a court found four of the accused, all Algerians, not guilty Friday and dropped charges against four — three Algerians and a Libyan — on Wednesday.

The only conviction was against Algerian Kamel Bourgass (search), 29, who was sentenced in June to life in prison for stabbing a policeman to death during a raid in northwest England on Jan. 14, 2003.

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When arrested, Bourgass had been on the run since another raid on a London apartment about a week earlier, where officers found recipes for ricin and other poisons.

Bourgass also was convicted on a charge of conspiracy to commit a public nuisance "by the use of poisons and explosives to cause disruption, fear or injury."

The conspiracy charge also had been leveled against the four other Algerians who were cleared Friday. Mouloud Sihali, David Aissa Khalef, Sidali Feddag and Mustapha Taleb had been charged after their fingerprints allegedly were found in the house where the toxin recipes were found.

Gareth Pierce, an attorney for three of the cleared men, said the charges were politically motivated.

"There was a great deal that this country was led to believe that in part caused it to go to war on Iraq, erected on the basis of an alleged major conspiracy involving ricin," Pierce said.

Ricin is derived from the castor bean plant and is one of the world's deadliest toxins. It has been linked in the past to Usama bin Laden's Al Qaeda terror network and Iraq. It has no known antidote and kills cells by preventing them from making proteins.

"This was a hugely serious plot because what it had the potential to do was to cause real panic, fear, disruption and possibly even death to the public," Peter Clarke, head of Scotland Yard's Anti-Terrorist Branch, said Wednesday after news of the verdict was released.

During the Jan. 14, 2003, raid, Bourgass stabbed Constable Stephen Oake to death and knifed three other policemen. Officers testified the raid was botched, the suspects were left without handcuffs for long periods and intelligence information was bad.

Defense attorney Michel Massih said prosecutors failed to prove conspiracy against the cleared men, alleging that the charges were hastily compiled and stressing that no ricin was ever found.

"There was not a single target of this conspiracy," Massih said.

Alleged coconspirator Mohamed Meguerba reportedly told police Bourgass had been planning to smear poison on the door handles of cars and buildings in London. Meguerba is awaiting trial in Algeria for alleged terrorist offenses.

In the London raid, police found recipes and ingredients for poisons including ricin, cyanide and botulinum, and the blueprint for a bomb.

Although no ricin was found, government scientists said the evidence showed attempts had been made to make the poison. Scientists who followed the recipes produced enough ricin and cyanide to kill hundreds of people, prosecutors said.

"These were no playtime recipes," prosecutor Nigel Sweeney said in the trial. "These are recipes that experts give credence to and experiments show work. They are scientifically viable and potentially deadly."

The raid was staged at a time when British authorities were warning of a serious threat of terrorist attack, but the officer's killing was the first reported fatality in Britain linked to terrorism since the Sept. 11 attacks in the United States.

Prime Minister Tony Blair described the stabbing as "an appalling tragedy and wicked in the extreme," and the killing dominated headlines.