Adel Mohamed Arnaout (born 1970) is an alleged criminal landed Lebanese immigrant of Albanian descent living in Toronto, Ontario, who is accused of sending three letter bombs out to residents of the Greater Toronto area in August 2007.
The first recipient of the letter bomb was Abdelmagid Radi on August 11, who sustained minor injuries on opening the letter. The second bomb was sent to real estate lawyer Terrence Reiber on August 19, who called police after noticing a petroleum-type odour coming form the letter. Police destroyed the letter bomb. Reiber had represented Arnaout in a previous criminal matter. The third bomb was received by Guelph, Ontario resident John Becker on August 22. The device failed to explode. Becker confirmed Arnaout had been a tenant at two of his Guelph properties 3 years earlier before being evicted.
Arnaout had a previous conviction for criminal harassment in April, 2003, for which he received a conditional discharge. The charge stemmed the harassing of managers of a Toronto modelling agency with which he had signed, hoping for a career as a male model. When Arnaout failed to get any work as a model, he allegedly began calling the agency repeatedly and threatening them, claiming to be a member of the Russian mafia. 
Police were already investigating Arnaout since June 2007 after harassment complaints by Toronto resident Steven Scott. Arnaout was wanted on an arrest warrant which had been was issued on June 26 charging him with criminal harassment of Scott, a former employer.
On August 30, 2007, Arnaout was taken into custody in connection to the letter bombs. At the time of his arrest, a rental car driven by him was found with 3 similar explosives inside. The Toronto Police bomb disposal unit did not defuse the explosives but instead transported them to the Leslie Street Spit where they were destroyed in a controlled explosion. The transport of the explosives by police closed the Don Valley Parkway and parts of the Gardiner Expressway for several hours. After his arrest, police also search his rental apartment in an East York home, nicknamed the Bombay Bunker.
Police indicated the bombings were not due to racial or terrorist motives.
Arnaout now faces three counts of attempted murder, three counts of attempt to cause an explosion, one count of illegal possession of explosives, and one count of criminal harassment.
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- Hertz, Barry (2007-09-05). "Letter bomb suspect may have acted on grudges". National Post. Retrieved 2007-09-09.