Bulgarian police on Wednesday released a composite picture of the man they think blew himself up on a bus packed with Israelis, killing six people last month in the Black Sea resort of Burgas.
The computer-generated picture shows a young man with fair skin, light-coloured eyes, a high forehead and short dark brown hair.
Experts had applied modern technology and techniques to the available data to restore "the face of the suicide bomber", said an interior ministry statement.
It urged Bulgarians to contact the ministry if they had any information about the man in the picture.
Investigators have been struggling to identify the suspected bomber. They found only his head and limbs after the July 18 attack, suggesting the bomb had probably been attached to his torso.
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They were unable to match fingerprints or DNA samples taken from the bomber with anything in international databases.
Last week, a Bulgarian website, bivol.bg, published the first pictures of the suspect's face after he was killed.
They showed a rather ravaged face, but one of the pathologists who carried out the autopsy, Kosio Yankov, confirmed the pictures were authentic
Yankov told the daily 24 Tchassa that the man's eyes were "between brown and green."
Galina Mileva, another pathologist who examined the attacker's remains, had earlier put his age at "between 25 and 30-something" and said the bomber had fair skin but could have been "of Arab origin."
The attack at Burgas airport, the first of its kind on Bulgarian soil, killed five Israeli tourists and a Bulgarian driver and injured around 30 people.
Israel has blamed Iran and its Lebanese "terrorist proxy" Hezbollah, but Tehran has denied any involvement.