The authorities in Turkey say they have identified the chief suspect in the murder of Hrant Dink, a prominent journalist of Armenian descent.
Police believe the suspect is tucking a gun into his trousers
The suspect, named as Ogun Samast, was reportedly identified by his father who saw his picture on television and then informed the police.
Dink, 53, had written extensively about the mass killing of Armenians by Turks during World War 1.
He was shot dead outside his newspaper offices in Istanbul on Friday.
The governor of Istanbul named Ogun Samast as the man whose image was captured on security cameras close to where Dink was killed.
Police released very clear images of a young man with an angular face and thin beard.
In one image he is seen running from the scene, tucking what officials say is a gun into his belt.
Mr Samast's family, from the Black Sea town of Trabzon, are now being questioned by police.
The governor said 12 people are currently being questioned in connection with the murder.
Dink's murder has shocked Turkey where Prime Minister Tayyip Erdogan has vowed repeatedly that the authorities will do whatever it takes to catch the killer.
Journalists and politicians in Turkey have expressed outrage at the killing, which many described as a political assassination, while the US, EU, France, and several human rights groups also voiced shock and condemnation.
Hrant Dink was one of Turkey's most prominent Armenian voices
Dink had received multiple death threats from nationalists because of his views on the mass killings of Armenians during the final days of the Ottoman Empire.
He was convicted in October 2005 for writing about the Armenian "genocide" in 1915, a claim denied by the authorities in Ankara.
The issue is a sensitive subject in both Armenia and Turkey. Many Armenians have campaigned for the killings to be recognised internationally as genocide.
The Armenian government has condemned Dink's murder.
Its president, Robert Kocharian, said the killing "raises numerous questions and deserves the strongest condemnation".
"We hope that the Turkish authorities will do everything possible to find and punish the culprit strictly in accordance with the law."
The speaker of Armenia's parliament, Tigran Torosyan went even further.
"Following the murder, Turkey should not even dream about joining the European Union," the Armenian news agency Arminfo quoted him as saying.
The two countries still have no official relations since Armenia gained independence after the break up of the Soviet Union in 1991.