Wissam al-Hassan, who led an investigation that implicated Syria and Hezbollah in the assassination of former prime minister Rafik al-Hariri, and seven other people were killed when the bomb exploded in central Beirut on Friday afternoon. 

Hassan, a Sunni Muslim who was close to Hariri, also helped uncover a bomb plot that led to the arrest and indictment in August of a pro-Assad former Lebanese minister, in a setback for Damascus and its Lebanese allies including Hezbollah.

  The bombing was the most serious to hit the capital since Hariri's 2005 assassination and prompted Sunni Muslims to take to streets across the country, burning tires and blocking roads in a show of sectarian anger. 

Hariri's son, Saad al-Hariri, accused Assad of being behind the bombing, while Lebanon's opposition March 14 bloc called on Prime Minister Najib Mikati's government, which includes ministers from Hezbollah, to resign over the bombing.