Two brothers in Germany and a Dutchman who lived in Belgium were arrested in September in connection with the attempt to import the drugs, seized Sept. 22 around the western city of Essen.
Police said a Syrian-Iraqi organized crime ring that has operated for years is believed to be behind this smuggling.
They refused to say whether the drugs were believed to have originated in Iran, or were hidden in the shipment en route.
In January, German customs agents found heroin in nine Iranian rugs shipped from Iran and the discovery led to the arrest of a number of people in France, Belgium and Poland.
Costumes officials in Germany said the unusual heavy weight of the carpets that arrived at an airport in the city of Leipzig raised suspicions of inspectors.
Later, when the shipment was inspected millions of dollars worth of refined heroin was found in the rugs. The heroin had been woven into the rugs.
The carpets were also due to be shipped to Africa.
The Iranian regime and its high ranking officials are involved in drug trafficking at the international level.