The owner of the ship that transported 2,750 tonnes of ammonium nitrate to Beirut's port in 2013 owed money to a bank accused of laundering funds for Hezbollah, an investigation by Der Spiegel and the Organised Crime and Reporting Project (OCCRP) has claimed.
According to the report, the true owner of the Moldavan-flagged MV Rhosus, was Cypriot businessman Charalambos Manoli, not the Russian Igor Grechuskin, as previously thought.
Manoli, who owned the vessel through a Panamanian-registered company with a Bulgarian postal address, was in debt to Lebanese-owned bank FBME at the time of the ship's last voyage.
The bank had loaned Manoli money to buy a new cargo ship in 2011, but almost immediately the Cypriot tycoon defaulted on the debt repayments and offered the MV Rhosus as collateral.
FBME was later accused of facilitating Hezbollah financiers after the US Treasury claimed one of the bank's clients was a known associate and financier for the Iranian-backed Shia militia.
The Lebanese-owned bank was later forced out of business by US sanctions, imposed because of the FBME's alleged ties to Hezbollah.
Meanwhile, Der Spiegel and OCCRP's joint investigation has also unearthed other previously unknown facts about the provenance of the ship and ammonium nitrate involved in the massive blast with rocked Lebanon's capital Beirut on 4 August.
According to the reports, Grechuskin only chartered the MV Rhosus and was the one who ordered the crew to make the unscheduled stop in Beirut.
The stop was for the ship to pick up additional cargo and deliver it to Jordan in order to raise sufficient funds to pay for the vessel's passage through the Suez Canal.
When the first truck of cargo damaged the ship's deck, however, the plan, and later the vessel and crew, were abandoned in Beirut.
In six years, neither the Georgia-based company that supplied the substance, nor the Mozambican firm that had ordered it made any attempt to retrieve the abandoned material from Lebanon, according to the report.
A British-based middleman for the deal, however, paid a Lebanese lawyer to petition authorities to inspect the ammonium nitrate, with the hope of recovering the abandoned material.
The report from the inspection in February 2015 stated the ammonium nitrate was in a poor condition, stored insecurely and held in ripped bags, according to OCCRP, leading the middleman to end attempts to recover the substance.
Moreover, the OCCRP reports only an estimated 1,900 tonnes of ammonium nitrate were found in Beirut, but the exact amount was never confirmed by Lebanese authorities.
It remains unclear what happened to the remaining tonnes of ammonium nitrate that arrived on the MV Rhosus in 2013, but the joint investigation ultimately claims the 4 August blast may have been caused by only 700 to 1,000 tonnes of the substance, rather than 2,750 tonnes.
Nevertheless, the explosion was one of the largest recorded non-nuclear blasts and has devastated Beirut, killing nearly 200 and injuring thousands more.