Police in four European nations raided homes and offices and detained 24 people today at the climax of an investigation into trading in an illicit synthetic drug, dpa reported. The suspects in Germany, Austria, Slovenia and Switzerland are likely to face charges of tax evasion, money laundering, criminal conspiracy and drug trafficking. German police in Munich said nearly 400 premises had been searched in the four nations. Police say the main substance traded by the group since 2007 was gamma-butyrolacton (GBL), an industrial solvent which can either be sniffed or used as a precursor in manufacturing "liquid ecstasy." Just one millilitre of GBL can make people feel euphoric and large amounts make them dizzy, unconscious or dead. Prosecutors in Nuremberg, Germany launched the inquiry last March after examining the activities of a 31-year-old German chemicals merchant said to have regularly sold GBL to drugs traders.