ANKARA, Turkey Turkish police say a New York City woman who went missing and was later found dead in Istanbul had suffered a fatal blow to the head.
Istanbul police chief Huseyin Capkin said Sunday that forensic experts had not concluded their autopsy report on the victim, Sarai Sierra, but that it was "clear" the head injury caused her death.
NTV, a Turkish broadcaster, says 15 people have been detained for questioning in the case.
In Washington, the U.S. State Department confirmed Sierra's death in Istanbul, thanked Turkey's government for its extensive efforts to locate her body and said the investigation of what happened to her would continue.
"We are also appreciative of the many expressions of sympathy received from the Turkish people," the State Department said in its statement.
Sierra, a 33-year-old mother of two, was last heard from on Jan. 21, the day she was to fly home from a vacation. Her body was discovered Saturday evening near the remnants of ancient city walls.
Sierra, whose children are 9 and 11, had left for Istanbul on Jan. 7 to explore her photography hobby and made a side trip to Amsterdam, Netherlands, and Munich, Germany. She had originally planned to travel with a friend, but ended up traveling alone when her friend canceled.
She was in regular contact with friends and relatives, and was last in touch with her family on Jan. 21, the day she was due back in New York. She told them she would visit Galata Bridge, which spans Istanbul's Golden Horn waterway, to take photos.
The body was found not far from the bridge and near a major road that runs alongside the sea of Marmara. Here tourists often photograph dozens of tankers waiting to access the Bosporus strait.
It was not clear if a Turkish man Sierra had exchanged emails with during her stay in Istanbul was among those being questioned. He was detained for questioning Friday, then released. Turkish news reports said Sierra had arranged to meet the man on Galata Bridge, but he reportedly told police the meeting never took place.
Shortly after her body was discovered, a woman came forward and told police she had seen a white car parked near the city walls as she was driving there the night of Jan. 29, Anadolu reported. She said a man was trying to remove "something" from the car.
"At that moment, I noticed a woman's hand," Anadolu quoted the woman as telling reporters after talking with police. The agency said she declined to give her name.
Sierra's husband, Steven, and her brother, David Jimenez, traveled to Istanbul to help search for her. Sierra's mother, Betzaida Jimenez, said Saturday that she couldn't talk about the case when reached in New York.