The Sofia city prosecutor's office is taking part in an investigation into whether citizens were murdered in 2022 in the Luhansk and Donetsk regions of Ukraine. A pretrial proceeding has been initiated on the matter, according to a Bulgarian state news agency report quoting the Sofia city prosecutor's office. Bulgaria’s participation in the investigation comes after Sofia backed a clause in Ukrainian President Volodymyr Zelenskiy’s peace formula that provides for the restoration of justice and the prosecution of war crimes committed in Ukraine. The State Agency for National Security (DANS) said that an investigation had been opened based on data showing that war crimes had been committed in Ukraine by members of the Wagner mercenary group.