A third suspect has been identified in the bombing of a bus that killed five Israeli tourists in the Bulgarian city of Burgas in 2012, Reuters reported on Thursday.

The tourists 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 was quoted as having told reporters.

“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, according to Reuters. He did not give any more details.

Six months into the investigation, Bulgaria said suicide the bomber who carried out the attack had been helped by two Lebanese-born Australian and Canadian passport holders with links to the military wing of Lebanese terrorist group Hezbollah.

Bulgaria later identified the accomplices as Australian national Meliad Farah, 32, also known as Hussein Hussein, and Canadian Hassan El Hajj Hassan, 25.

The revelation of Hezbollah’s involvement in the attack contributed to an EU-wide decision last year to blacklist Hezbollah as a terror group. However, the EU chose to only blacklist Hezbollah’s “military wing”, leaving its political faction off the list.

It has also been reported that Hezbollah wired almost $100,000 (75,000 euros) to the two suspects wanted in the attack.

Several months ago, Bulgaria said it planned to place the suspects on trial by April.