A U.N.-backed tribunal has indicted four members of militant group Hezbollah, which along with its allies now holds a majority in Lebanon's Cabinet. Hezbollah denies involvement in Hariri's killing and has refused to extradite the suspects.
Al-Hassan's department also had a role in breaking up several Israeli spy rings inside Lebanon over the past few years, Lebanese officials said.
Member of former Prime Minister Saad Hariri's parliamentary bloc Nuhad Mashnouk said al-Hassan's funeral will be held in Beirut Sunday afternoon and the late general will be buried next to Hariri's tomb.
Lebanon's top Sunni cleric, Grand Mufti Mohammed Rashid Kabbani, condemned al-Hassan's assassination, calling it a "criminal explosion that targets Lebanon and its people." He called for self-restraint, saying "the criminal will get his punishment sooner or later."
Police and army troops sealed off the site of Friday's blast as military intelligence agents investigated what was the deadliest bombing in Beirut in four years.
Rafik Khoury, editor of the independent Al-Anwar daily, said the assassination was an attempt to draw Lebanon into the conflict in Syria, which has been the most serious threat to the Assad family's 40-year dynasty.
"The side that carried the assassination knows the reactions and dangerous repercussions and is betting that it will happen. Strife is wanted in Lebanon," Khoury wrote.
Sharbal Abdo, a Beirut resident who lives down the block from where the car bomb detonated, on Saturday brought his six-year-old son Chris and 12-year-old daughter Jane to see what happened the day before. They were both at school when the blast ripped through the area.
"They were very afraid yesterday, and cried a lot late into the night," Abdo said. "Today I decided to bring them here and show what happened. They need to face this situation. It may be their future."
Associated Press writer Barbara Surk contributed to this report.
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