[5] In August 2020, the Special Tribunal for Lebanon found Salim Ayyash, a mid-level operative in Hezbollah, guilty in absentia of five charges including the premeditated murder of Hariri using explosive materials.

Hariri and others in the anti-Syrian opposition had questioned the plan to extend the term of Lebanese President Émile Lahoud, emboldened by popular anger and civic action that became the Cedar Revolution.

Lebanese Druze leader Walid Jumblatt, a newer recruit of the anti-Syrian opposition, said after the assassination that in August 2004 Syrian President Bashar al-Assad threatened Hariri personally in a meeting, saying "Lahoud represents me...

The mission has also received accounts of further threats made to Hariri by security officials in case he abstained from voting in favour of the extension or "even thought of leaving the country.

"[12] On the other hand, then-Vice President Abdul Halim Khaddam who defected from the Syrian branch of the Arab Socialist Ba'ath Party due to Assad's handling of the Lebanese crisis stated in an interview to Al Arabiya that Bashar threatened Hariri with "extremely harsh words".

[15] A tape aired by Al Jazeera showed a bearded man, believed to be a Palestinian named Ahmad Abu Adas, claiming the attack.

[9] A 2015 report by The New York Times states that DNA evidence shows Adas was not the bomber, but had been lured into making the video in order to cast blame on the Sunnis, and was then probably killed.

[2] The UN report determined that the bomb had been placed in a white Mitsubishi Canter truck, based on CCTV footage from a nearby HSBC bank.

[9] On 7 April 2005 the United Nations Security Council unanimously adopted Resolution 1595 to send an investigative team to look into Hariri's assassination.

The report implicated Syrian and Lebanese officials, with special focus on Maher al-Assad, Assef Shawkat, Hassan Khalil, Bahjat Suleiman, and Jamil Al Sayyed.

"[21]In the wake of the report, U.S. President George W. Bush called for a special meeting of the UN to be convened to discuss international response "as quickly as possible to deal with this very serious matter.

[citation needed] Lebanese politicians asked to extend the investigative team's duration and charter, to include assassinations of other prominent anti-Syrian Lebanese figures around that time, such as journalist Samir Kassir (killed by a car bomb in June 2005) and Gebran Tueni (also killed by a car bomb, in December 2005).

[24] The UN Security Council voted unanimously to demand full Syrian cooperation with UN investigators in the matter, and Brammertz's last two reports[when?]

[25] On 30 August 2005, four pro-Syrian Lebanese generals (some of whom had promoted the false Abu Addas theory) were subsequently arrested under suspicion of conspiracy to commit murder.

[26] Mustafa Hamdan, former head of the Lebanese Presidential Guard brigade; Jamil Al Sayyed, former director-general of Security General; Ali Al Hajj, director general of the Lebanese Internal Security Forces; and Raymond Azar, the former director of the Military Intelligence were released upon an order from the STL pre-trial judge at the request of the prosecutor due to lack of evidence.

[32] On 18 December 2006, a progress report by former head of the investigation, Serge Brammertz, indicated that DNA evidence suggested that the assassination might be the act of a young male suicide bomber.

[36] On 7 February 2012, Hürriyet reported investigators from the United Nations interviewed Louai Sakka, interested in whether he had played a role in the assassination.

[38] Upon request from a majority of members of the Lebanese parliament[39] and the Prime Minister,[40] the United Nations Security Council adopted Resolution 1757, implementing the agreement.

The premises of the tribunal is the former headquarters of the Dutch General Intelligence and Security Service (Algemene Inlichtingen- en Veiligheidsdienst, or AIVD).

Considered as Syria's main rule-enforcing agents at the time, they spent nearly 3 years and 8 months in detention after Lebanese authorities arrested them on 1 September 2005, and during that period no charges were ever pressed against them.

"[citation needed] On 30 June 2011, Haaretz reported that the Tribunal had submitted to Lebanon's Prosecutor General indictments of four Lebanese Hezbollah members, and a foreigner.

[55] On 18 August 2020, the Special Tribunal for Lebanon found Salim Ayyash, a mid-level operative in Hezbollah, guilty in absentia of five charges including the intentional murder of Hariri with premeditation by using explosive materials.

[5][56] This was in spite of the fact that already by 2015 the tribunal (based on earlier work by Lebanese police captain Wissam Eid, who was assassinated in 2008) had uncovered five groups of cellphones involving scores of operatives.

[2] In 2022, Hassan Habib Merhi and Hussein Oneissi, two Hezbollah members, were also convicted by the Special Tribunal for Lebanon for their roles in the assassination.