Egyptian newspapers on Thursday published a digital sketch created by the authorities of the man suspected to be behind the New Year's Eve church bombing in the city of Alexandria, DPA reported.
The bomber is believed to have been between 23 and 25 years old, according to state newspaper al-Ahram.
A bag believed to have contained between 20 and 25 kilograms of explosives was found near the remains of the suspected bomber.
Investigators created the sketch based on pieces of evidence found at the bombing site, including parts of the dead bomber's face.
A picture of the bomber's severed head was published in several Egyptian newspapers alongside the digital sketch.
The bombing outside the Coptic Church of the Saints in the coastal city of Alexandria took place during an evening mass on New Year's Eve, killing 23 people and leaving at least 100 injured.
Daily protests since the attack have taken place throughout the country, with a number of both Muslim and Christian demonstrators injured in clashes with police and others arrested.
"We cannot prevent people from expressing their sorrow, yet I ask them to express their feelings without violence," said Egypt's Pope Shenouda III, the patriarch of the Coptic Orthodox Church, in an interview earlier this week with Egyptian state TV.
Copts are preparing to celebrate their Christmas on January 7, with thousands of Muslims planning to stand outside churches to offer protection and support.
Official figures estimate Coptic Christians comprise 10 to 15 per cent of Egypt's population.