The government formed an investigative committee led by Prime Minister
Hassan Diab, which announced it would submit its findings to the
Council of Ministers of Lebanon by 11 August 2020. The committee includes the justice, interior and defence ministers, and the head of the top four security agencies: the
Armed Forces,
General Security,
Internal Security Forces, and
State Security. The investigation was to examine whether the explosion was an accident or due to negligence, and if it was caused by a bomb or another external interference.
President Michel Aoun rejected calls for an international probe despite demands from world leaders. On 5 August, the Council agreed to place 16 Beirut port officials who had overseen storage and security since 2014 under
house arrest, overseen by the army, pending the investigation into the explosions. In addition, the general manager of the port, Hassan Koraytem, and the former director general of Lebanon's customs authority, Shafiq Merhi, were arrested. Later, on 17 August, the incumbent director-general of Lebanon's customs authority, Badri Daher, was also arrested. Also, former ministers of both finance and public works were due to be interrogated by a judge appointed by the council. In the meantime, state prosecutor Ghassan Oueidat ordered a travel ban on seven individuals, including Koraytem. While Acting Justice Minister
Marie-Claude Najm unsuccessfully demanded an international investigation into the blast, she also noted that "...this case is a chance for the Lebanese judiciary to prove they can do their jobs and win back the confidence of the people". On 19 August, a Lebanon judge ordered the arrests of more suspects over the explosion, making the total number of accused 25. The Lebanese judge
Fadi Sawan, who has been responsible for the investigation, summoned former Minister of Transportation and Public Works
Ghazi Aridi, Labor Ministers
Ghazi Zaiter, Youssef Fenianos, and
Michel Najjar, General Director of the
Lebanese State Security Tony Saliba, Director General of Lebanon's Land and Maritime Transport division, Abdul-Hafeez Al-Qaisi, and General Director of General Security, Major General
Abbas Ibrahim. In September, Lebanon's state prosecution asked
Interpol to
detain two Russian citizens, the captain and the owner of
Rhosus, as its cargo of ammonium nitrate was blamed for the explosion. In January 2021, Interpol issued
Red Notices against the two
Russians as well as a
Portuguese man. In December 2020, Lebanon's outgoing Prime Minister Diab and three former ministers were charged with negligence over the Beirut port explosion. They were
Ali Hassan Khalil, finance minister in 2014, and between 2016 and 2020, and two ministers of public works. Ghazi Zeitar was transport and public works minister in 2014, and followed by Youssef Fenianos between 2016 and the beginning of 2020. In an interview with
Reuters at his home in
Damascus on 28 January 2021, Syrian-Russian businessman
George Haswani denied any links to the Beirut explosion knew nothing about a company linked to the process of buying a shipment of chemicals that exploded. Haswani said that he had resorted to the Cypriot company Interstatus to register his company, which is the same agent that registered the Savaro company, and that the agent company had moved the registration site of the two companies to the same address on the same day. However, Haswani said that he did not know anything about Savaro and that any links between it and his company are just a coincidence because the two companies have the same agent. As stated in previous reports, Reuters was unable to determine whether Haswani had anything to do with Savaro. Haswani said, "I don't know what other companies are registered by this Cypriot company, five or three or 70 or more... It is a fabricated media whirlwind. We don't know Savaro and we hadn't heard about them before this." Interstatus did not respond to a request for comment. Marina Psyllou, the director of Interstatus, was listed in the registration documents of the company (Savaro) as the only owner and director of the company, but she denied that she was the real manager of the company. She told Reuters in mid-January 2021 that the beneficial owner of the company was another person, whom she refused to identify. She added that Savaro was a dormant company that had never conducted business. Haswani said that he was not contacted by any investigators from Lebanon or any other country regarding the explosion and that he would soon work to file a legal case in
Paris against media reports linking him to the explosion. He continued, "I am living my life normally and laughing because I am someone who knows well that I have nothing to do with this matter at all. Why would I worry?" On 15 April 2021, six detained people were released, including two officers, although they were not allowed to travel out of Lebanon. In September 2021, the
OCCRP published an investigation that linked Savaro Limited to a Ukrainian company trading chemicals, directed by Ukrainian citizen Volodymyr Verbonol. The report also mentioned that only 20 percent of the nitrate originally stored in the warehouse was actually left when it exploded, raising questions about what happened to the rest. On 14 October 2021, six people were killed and at least 30 injured in a
gunfire exchange in Beirut during protests by members of the Shia
Amal and
Hezbollah outside the Justice Palace, demanding an end to the investigations led by Judge
Tarek Bitar, who they deemed too much centered on their political allies. On 21 November 2021, the
BBC reported that legal groups representing victims of the blast had sent letters on three occasions to
UN Secretary General Antonio Guterres requesting more information from UNIFIL, but had received no acknowledgment from the UN. A day later, the Lebanese Foreign Minister Abdallah Bouhabib announced that Lebanon had received from Russia satellite images of the port from the day of the blast in 2020. These were the first official images made available by any foreign government. Throughout 2022 the investigation stalled. As of 8 June, parliamentary immunity, as well as outstanding complaints and other procedural roadblocks initiated by two members of Parliament and former ministers Ali Hassan Khalil and Ghazi Zaiter, continued to prevent significant progress. On 16 January 2025, the investigation was resumed following the nomination of
Nawaf Salam as prime minister and the
Israel–Hezbollah conflict. Ten people were charged, including security, customs and military personnel. On 12 May 2025 it was reported that Judge Tarek Bitar was set to issue an indictment on 4 August 2025, coinciding with the disaster's fifth anniversary. It was claimed that he had completed his examination of the ammonium nitrate shipment's origin, entry into the port, and subsequent detonation. He planned to finalise remaining interrogations before releasing the indictment. In September 2025, Igor Grechushkin, a Russian businessman with Cypriot citizenship, was arrested in
Sofia International Airport,
Bulgaria, under an
Interpol red notice issued by Lebanon, accused of being linked to MV
Rhosus. On 10 December 2025, it was reported that a court in Bulgaria rejected Lebanon's extradition request. In December 2025, the
Israel Defense Forces claimed that Hezbollah's assassination squad had targeted Lebanese individuals who linked the organization to the explosion. The assassinated individuals were journalist
Lokman Slim, known for his criticism of Hezbollah, photographer Joe Bejjani, who connected Hezbollah to the explosion, the head of customs inspections at Beirut port, Joseph Skaff, ==Relief operations==