A third suspect has been identified in the bombing of a bus that killed five Israeli tourists in the Black Sea city of Burgas in 2012 that Bulgarian authorities have blamed on the Lebanese militant group Hezbollah .
The tourists had arrived on a charter flight from Israel and were in the bus in the airport car park when the blast tore through the vehicle, also killing the Bulgarian driver and wounding more than 30 people.
"Two individuals were previously established. They are now three," Chief Prosecutor Sotir Tsatsarov told reporters on Thursday.
"The identification of the new suspect will extend the investigation and there will be new requests for legal help from abroad... It means we will need just a little more time," Tsatsarov said. He did not give any more details.
Bulgarian authorities previously named two men of Lebanese origin as suspects and said it believed the Shiite Muslim group Hezbollah was behind the bombing.
The European Union last July put the armed wing of Hezbollah on its terrorism blacklist over the incident.
Hezbollah denies any involvement.
Prosecutors in November said they aimed to wrap up the investigation by the end of April.