The man suspected of killing Scottish aid worker Elisabeth Jane Ross in Greece is 26-year-old Sharif Ahmadzai, the BBC understands.
He was arrested after the body of the 38-year-old was found in a suitcase in an abandoned building in the Kypseli district of Athens on 18 July, several days after she was reported missing.
Ahmadzai, who was born in Afghanistan and is a champion boxer, travelled to Greece as a refugee.
He is expected to appear in court in Athens on Wednesday.
The BBC understands Ahmadzai, who left Afghanistan after being orphaned aged 15, lives in Greece with his American wife and child.
His father, a commander in the Afghan army, was shot dead and his mother and siblings were killed by a suicide bomber in Kabul.
He travelled to Greece via Iran and Turkey, according to a video telling his story, external which was published by the International Federation of Red Cross and Red Crescent Societies (IFRC), before settling in a refugee camp on the island of Lesbos.
It is understood this is where he met his wife and converted to Christianity. The pair then set up the charity Love Every Nation Athens to help other refugees.
It is thought that he met Ross through the charity.