Bulgarian police released a composite image Wednesday of the man accused of carrying out a suicide bomb attack on a bus at Burgas airport last month, in which five Israeli tourists and the Bulgarian bus driver died.
The image shows the face of a clean-shaven young man with short dark hair, a pale complexion and brown or green eyes.
It was created by applying "modern technologies and techniques" to the data collected, the police said in a statement.
Anyone with more information about the man pictured is urged to contact the authorities.
More than 30 other Israelis were injured, some seriously, in the terror attack two weeks ago. The Israelis had arrived from Tel Aviv to take a vacation at a resort on Bulgaria's Black Sea coast.
The bomb is believed to have been concealed in a backpack the suicide bomber placed on a bus in a parking lot outside the airport.
Bulgarian authorities have struggled to identify the bomber, who was seen on airport security videos about an hour before the attack. In that video, he had long hair and wore a baseball cap.
Bulgarian Interior Minister Tsvetan Tsvetanov said last month that the man was a foreigner who had entered the country with fake identification documents and had been in Bulgaria for at least four days.
The Interior Ministry has said it is not ruling out the possibility that the bomber had help.
Israel said it suspected that Iran or an Islamist militant group such as Hezbollah was behind the attack, adding to tension between Israel and Tehran. Iran, which condemned the attack, rejected Israel's claims.