Denmark`s supreme court Wednesday ruled illegal the detention without trial of one of two Tunisians held for allegedly plotting to kill a cartoonist who satirised the Prophet Mohammed.

The two were arrested on February 12 on suspicion of planning to murder Kurt Westergaard, one of 12 cartoonists whose drawings of Islam`s prophet in a Danish newspaper in 2005 sparked worldwide controversy.

They had been held in custody pending a government-ordered expulsion, a measure recommended by the Danish intelligence agency PET which considered them a threat to national security. Their guilt was never established in a trial however.

The Supreme Court said in a statement that PET did not have sufficient evidence to detain the 37-year-old suspect, reportedly named Slim Chafra, who was released in October after being granted a special residency status in Denmark, since he could not be extradited to Tunisia due to the risk of torture.

The special status is granted foreigners convicted, or in Chafra`s case suspected, of serious crimes but who cannot be expelled. They are prohibited from working or drawing social security benefits in the Scandinavian country.

The high court judges however ruled that there was reason to detain Chafra`s 26-year-old compatriot, whose name was not given, based on evidence presented by PET to lower courts.

Evidence gathered during searches of the man`s apartment as well as witnesses placing him near Westergaard`s made it reasonable to believe he had been planning an attack on the cartoonist, they said.

The 26-year-old chose in August to leave Denmark with his wife and travel to an unknown European country to avoid remaining in prison indefinitely without trial.