Mohamedou Ould Slahi

Mohamedou Ould Slahi (Arabic: محمد ولد صلاحي, transliterated Muhammad Walid Salahi, also used the alias أبو مصعب, transliterated Abu Musab) (c.1972 - present) is a Mauritanian national suspected of involvement in one of the 2000 millennium attack plots.

Slahi was born in Mauritania, but moved to Germany in the late 1980s. He was well-known to investigators as an al-Qaida operative. In late 1999, Slahi was operating under the pseudonym "Abu Musab", unbeknownst to German or American intelligence.

Separately, members of the terrorist Hamburg cell were planning to go to Chechnya to defend muslims against Russian forces. They met a stranger on a bus named Khalid al-Masri, and advised them to talk to a man named Abu Musab (actually Slahi) in Duisberg, Germany. Slahi advised them that it was difficult to get to Chechnya, and many muslims were being turned away by the authorities. He therefore advised them to train in Afghanistan, and he gave them useful information in how to get there. In Afghanistan, these same travellers would become the core organizers of the September 11, 2001 attacks.

Afterwards, Slahi moved to Montreal, Canada and was granted permanent resident status despite security officials' concerns. He lived in a mosque as an imam. After the 2000 millennium attack plots failed, investigators began to suspect Slahi's involvement. The would-be suicide-attacker Ahmed Ressam had lived in the same mosque. Slahi moved suddenly to Mauritania, leading investigators to conclude he was fleeing; Slahi claims he went to visit his sick mother.

In Mauritania, Slahi was repeatedly arrested and released. Finally he was arrested and turned over to American forces, who placed him in Camp X-ray in Guantanamo Bay, Cuba. He received some notice later when he went on a hunger strike to protest the fact that a severe rash he had developed was not being treated. He finally received medical treatment after he became ill from exhaustion.