The Russian owner of a cargo ship linked to a cargo of ammonium nitrate at the center of the massive Beirut port explosion in 2020 has been arrested in Bulgaria, Lebanese judicial officials said Monday.

The arrest of Igor Grechushkin comes nearly five years after a Lebanese investigative judge issued two arrest warrants through Interpol for him and the vessel’s captain, Boris Prokoshev, also a Russian citizen.

The judicial officials said papers are being prepared requesting the transfer of Grechushkin to Lebanon for questioning. They said that if Grechushkin is not handed over, Lebanese investigators could travel to Bulgaria to question him there.

The four Lebanese judicial officials said Grechushkin, who also has Cypriot nationality, was arrested last week at Vasil Levski Sofia airport after arriving on a flight from Cyprus. They spoke on condition of anonymity in line with regulations.

The Aug. 4, 2020, blast killed at least 218 people and wounded more than 6,000 others. It devastated large swaths of Beirut and caused billions of dollars in damages.