There are serious doubts about the credibility of the statements of the main witness upon which the Detlev Mehlis’ investigation was based on. Detlev Mehlis is the UN special investigator of the assassination of Hariri. Suheir al-Sadik and is, in fact, a known con man who has been convicted several times. al-Sadik, 42 years old, who claims to be a member of the Syrian secret services, is the key witness who has helped to involve the services of the Syrian state in this assassination. However, he was sentenced several times for embezzlement and fraud in the past. Even the members of the investigative commission have serious doubts about the veracity of his statement.
Different members of this commission said that Sadik lied to them several times. For instance, Sadik initially told them he had left Beirut a month before the attack. But last September, he changed his statement and said he was one of the organizers of the attack. His apartment in the outskirts of Beirut had served as general headquarters for preparation of the attack and high-ranking officers of the Syrian secret services had stayed there. Being paid for his testimony wouldn’t be strange. According to his brothers, Sadik contacted them from Paris to tell them: “I’m a millionaire.”
Skepticism is also based on the fact that Sadik got in touch with Mehlis thanks to Syrian dissident Rifaat El Assad, president Bachar El Assad’s uncle and well-known enemy. Several weeks ago, the Syrian government sent several chanceries a file full of documents accusing Sadik with the purpose of proving that Mehlis was deceived by a notorious liar, a specialist in organizing tall stories.

Source
Der Spiegel (Germany)
Circulation: 1 100 000 copies. An important investigation magazine issued for the first time in 1947, and source of multiple political scandals. It is known for its own journalistic slang and also issues four special editions yearly. The website of the Spiegel is the most successful online magazine in Germany.

Zentraler Zeuge in Mehlis-Report ist verurteilter Betrüger”, by Ghaith Abdul-Ahad , Der Spiegel, October 26, 2005.