Bulgarian officials say they will investigate reports that a third suspect in the 2018 nerve-agent attack on a former Russian spy in Britain may have also been involved in a 2015 poisoning in Bulgaria.
A parliamentary committee on February 9 said it will next week request information from the Bulgarian intelligence services following a report published on February 7 by the British-based open-source investigation group Bellingcat.
The investigation centers on the poisoning of local businessman Emilian Gebrev, said Tsvetan Tsvetanov, the parliamentary leader of the ruling GERB party.
He said the probe would be coordinated with foreign partners.
"I am certain that the necessary coordination has already been set up between the Bulgarian, British, and European authorities on the case and they are working actively on it," he said.
Bellingcat, along with its Russian partner, The Insider, said the suspected Russian security agent arrived in Bulgaria in April 2015, just days before Gebrev and his son became seriously ill after being poisoned by an unidentified substance.
Bellingcat said the 45-year-old agent, who traveled under the alias Sergei Vyacheslavovich Fedotov, had been "conclusively identified as an agent of Russian military intelligence," known as the GRU.
According to Bellingcat, Fedotov flew from Moscow to Burgas, a resort on Bulgaria's Black Sea coast, on April 24, 2015, just days before Gebrev collapsed at a reception on April 28, 2015, and fell into a coma with symptoms of severe poisoning.
Gebrev, a veteran of the Bulgarian arms industry, and his son survived, as did a company executive who was treated with similar symptoms.
RFE/RL's Bulgarian Service quoted Bulgarian government sources as saying a foreign intelligence service had contacted its counterparts in Sofia when suspicions arose that Fedotov had traveled to Bulgaria.
The Kremlin immediately cast doubt on the findings of the new Bellingcat investigation and earlier reports of a third suspect in the nerve-agent attack on Sergei Skripal and his adult daughter in Salisbury, England, in March 2018.
"How is it possible that the use of some chemical warfare agent in Europe goes unnoticed in 2015? Why did we find this out only now?" Kremlin spokesman Dmitry Peskov said on February 8, referring to the Bulgarian case, while not completely denying it.
Moscow has denied it had any involvement in the Skripal poisoning, which led to a series of sanctions against Russia by the West and tit-for-tat diplomatic actions.
Skripal and his daughter were discovered unconscious on a Salisbury park bench after they had been poisoned by the highly toxic nerve agent Novichok in an attack the British government says was "almost certainly" approved by the Russian state.
Both survived after weeks in critical condition, but Dawn Sturgess, a woman who authorities said came in contact with the poison after her boyfriend found a fake perfume bottle containing it, died in July.
On September 5, British authorities announced they had charged two Russian men -- identified by their presumed aliases of Aleksandr Petrov and Ruslan Boshirov -- with carrying out the poisoning on March 4.
Bellingcat later identified the two as Aleksandr Mishkin and Anatoly Chepiga, both of whom work for Russia's GRU intelligence services. Despite Russian denials that they were involved, both men are now the subject of EU sanctions.
Bellingcat's latest report stated that Fedotov is also suspected of being involved in the British attack, having arrived in Britain two days before the Skripals were poisoned.