SOFIA, Bulgaria (AP) — Bulgarian authorities on Friday identified three Russian nationals who have been charged in absentia over the attempted murder, by poison, of the owner of a Bulgarian arms factory and two other people.

The three suspects have been identified as Sergei Pavlov, Sergei Fedotov, and Georgy Gorshkov, and are believed to be residents of Moscow, the prosecutor’s office said in a statement.

Last month, prosecutors announced charges against three Russians for the same case but did not identify them.

They were accused of having attempted to kill the victims “in a way endangering the lives of many” using a phosphorus-like substance.

In 2015, Emilian Gebrev, his son and a company employee fell ill after the poisoning but survived the attack.

The investigation into the Gebrev poisoning was reopened at the end of 2018 because of suspicions that the substance used in Bulgaria was similar to that in the poison attack on Russian ex-spy Sergei Skripal and his daughter, Yulia, in the English city of Salisbury that same year.

Bulgarian investigators say they have established that Russian military intelligence officer Sergei Fedotov, who was allegedly involved in the Skripal poisoning, visited Bulgaria on three occasions in 2015.

Gebrev has been involved in arms production and trade for several decades. According to media reports, arms produced in his factory have been exported to Ukraine.