They include Major-General Assef Shawkat, 55, the head of Syria's powerful military intelligence and brother-in-law of President Bashar al-Assad.
He is married to Assad's only sister, Bushra.
Shawkat was promoted to chief of military intelligence on 18 February, four days after al-Hariri's killing, replacing General Hassan Khalil after he was retired.
Shawkat headed another branch of military security from the 1980s to 2003.
A member of the ruling Alawite sect, he is close to al-Assad and regarded by many as the one who pulls the strings behind the scenes.
A second figure is Lieutenant-General Rustom Ghazali, a 55-year-old Sunni Muslim from the southern Houran region, who became Syria's chief of intelligence in Lebanon in October 2002.
Ghazali succeeded the late Ghazi Kanaan, who officials say committed suicide on 12 October.
Kanaan, Syria's interior minister since 2004, was intelligence chief in Lebanon for two decades.
Ghazi Kanaan is said to have
committed suicide in his office
Prior to Syria's military withdrawal from Lebanon in April, Ghazali was close to the country's then security chiefs, now in custody on charges of murder in connection with al-Hariri's murder.
Before succeeding Kanaan, Ghazali was intelligence commander in Beirut, his headquarters at the notorious Beau Rivage Hotel, a Syrian detention centre where many Lebanese believe torture and abuse were widespread.
In June, the US Treasury Department froze Ghazali's and Kanaan's assets.
Lebanon's central bank opened up their accounts to investigators last month.
Farouq Sharaa has been the face of Syria's foreign policy for more than two decades.
Farouq Sharaa is accused of
giving false statements
A trusted aide of late Syrian President Hafiz al-Assad, he supervised the Arab country's now-stalled peace talks with Israel from 1991.
First appointed as minister of state for foreign affairs in 1980, Sharaa was elected to the ruling Baath party's central committee in 2000 and its regional command this year.
Sharaa is accused in the report of giving false statements about his meetings with al-Hariri.
Lebanon's Major-General Jamil al-Sayyed served in the army for 30 years before he was appointed to the country's top security post, head of general security, in 1998.
He resigned in May under heavy pressure from the opposition in the aftermath of al-Hariri's assassination.
A Shia Muslim from the eastern Bekaa Valley, Sayyed was close to Ghazali and Kanaan.
Sayyed, 55, was arrested in August, along with three other generals, and charged with murder in connection with the al-Hariri assassination.
Brigadier-General Mustapha Hamdan, one of President Emile Lahoud's closest aides, had been the head of the Republican Guard since 1998, when Lahoud first came to office.
He is a Sunni who at one time during Lebanon's 1975-1990 civil war was a member of an anti-Syrian party, Al Murabitoun.
Hamdan was first to be put in charge of protecting Lahoud in 1990, when he was still army commander.
He was the only general to keep his post in the aftermath of al-Hariri's death but handed himself in on 30 August.
Major-General Ali Hajj was appointed head of internal security in 2004, by then Interior Minister Suleiman Franjieh, a strong ally of Syria.
Hajj was in charge of government protection for al-Hariri from 1992 until 1998.
He was appointed police chief for the northeastern Bekaa after al-Hariri resigned.
During that time, he became close to the Syrian leadership in Lebanon based in Anjar, near the border with Syria.
When al-Hariri returned to office after the 2000 parliamentary elections he removed Hajj from his protection after he found out Hajj was spying on him on behalf of Syria.