Turkish prosecutors say the teenager suspected of murdering Turkish-Armenian journalist Hrant Dink has confessed.
Ogun Samast has been returned by police to Istanbul
Ogun Samast was arrested after he was identified by his father from CCTV images taken near the scene of Friday's killing in Istanbul.
Prosecutors say he confessed after being detained in the Black Sea port of Samsun, before he was returned to Istanbul for further questioning.
Mourners have held a vigil at the site of the killing for a third day.
Many of the crowd had pictures of Dink pinned to their chests.
Dink, 52, was shot dead in broad daylight outside the office of his newspaper, Agos.
He wrote many controversial articles about the mass killing of Armenians by Ottoman Turks during World War I.
Port city arrests
Istanbul governor Muammer Guler announced the details of the capture in a live television broadcast late on Saturday.
He said police captured Ogun Samast, aged 16 or 17, late on Saturday on a bus in Samsun still carrying the gun allegedly used in the murder.
He was apparently returning to his hometown of Trabzon from Istanbul.
Six other suspects were picked up in Trabzon and four have been returned to Istanbul.
One was named as Yasin Hayal, a friend of Ogun Samast, who has spent 11 months in jail for a 2004 bomb attack outside a McDonald's restaurant in Trabzon.
Three other suspects detained in Istanbul on Friday shortly after the killing have been released.
Ogun Samast was identified by his own father when he saw television images taken by a security camera near the scene of the murder.
Turkish television showed images of a young man apparently running from the scene, tucking what officials said was a gun into his belt.
Dink's secretary told investigators Ogun Samast had asked to meet Dink earlier on Friday, before the killing, Mr Guler said.
After the request was turned down, the secretary saw the teenage suspect waiting on the street outside Dink's office, he said.
Dink's murder shocked Turkey and Prime Minister Erdogan vowed repeatedly that his killer would be caught.
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.
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.