The New York photographer murdered in Istanbul had sex in a restaurant toilet with a secret lover before being bludgeoned to death.
Mother-of-two Sarai Sierra, 33, met with her lover the day before she went missing and had sex with him in the bathroom of a local bar, local media said.
The lawyer of the man, who has only been identified as Tarkan K, says he began corresponding with Sierra around four months before they met.
Ozkan Polat said Tarkan met Sierra online and that she had contacted him saying she was visiting Turkey and wanted to meet. Tarkan denies any wrongdoing.
Sierra's body was found last Saturday, 12 days after she failed to catch her return flight from Turkey.
She had gone on holiday alone after a friend dropped out of the trip at the last minute.
According to reports, Sierra was not wearing any trousers when she was found - they were discovered torn nearby. However, investigators said there was no sign of sexual assault.
Sierra was last seen on CCTV wearing a coat and carrying a handbag - neither were with her body, which was found near the remnants of the city's ancient walls.
Tried to fight off attacker
Turkish authorities determined that Sierra died from a blow to the head. Earlier this week, police dogs were scouring the area where she was found.
The Milliyet newspaper said police are examining forensic evidence from Sierra's fingernails, hair and a blanket found near her body.
It said nail scrapings suggest she may have tried to fight off an attacker. Prosecutors got a court order on Monday to take blood and DNA samples from 21 people being questioned about her death.
Sierra's body was flown back to New York yesterday and her funeral is due to take place next week.
She will be buried in the church where she met and married her husband Steven Sierra.
He was planning to tell their two children, aged nine and 11, about their mother's death when he returned from Istanbul.
Sierra had gone to Istanbul to indulge her photography hobby and had made side trips to Amsterdam, Netherlands and Munich.
She left on 7 January and had been in regular contact with her family throughout the trip.