Sarai Sierra's husband, Steven, identified the body in Istanbul.

ISTANBUL — Turkish police say a New York City woman who went missing and was later found dead in Istanbul 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.

Capkin said more than 10 people were being detained and interrogated in the case. The Turkish daily Hurriyet reported that 22 people, including two women, had been interviewed.

Sierra, 33, a Staten Island mother of two, was found dead Saturday evening, almost two weeks after she was reported missing, Turkish police confirmed to USA TODAY.

Sierra's husband, Steven, identified the body Sunday, according to Turkish media reports.

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.

STORY: Missing American woman found dead in Turkey

Sierra's skull was broken when she was found dead Saturday evening at the foot of the city walls in the Sarayburnu district of Istanbul, Yener Ülgütol, the city's deputy manager of public security, told the Turkish daily Hurriyet.

Turkish media said police found a blanket with the body, suggesting Sierra was killed someplace else, then moved to the site where her body was discovered. Ülgütol said the blanket may have been there before she was killed.

After the body was discovered, a witness went to police, claiming she saw something suspicious Tuesday night while driving past the city walls, according to Turkish media. The female witness said she saw two men pulling something out of a car.

"At that moment, I noticed a woman's hand," the state-run Anadolu Agency quoted the woman as telling reporters after talking with police. The agency said she declined to give her name.

Sierra's jewelry, including a golden ring, a golden wristband and a necklace, were found on her body, but her tablet computer and smartphone were missing, investigators told Turkish media. The phone was turned on twice last week, police told Turkish media. Police found Sierra's driver's license on the body, according to reports.

Police are considering the possibility that the murder could have been committed soon after Sierra went missing Jan. 21 and that the body may not have decayed because of the seasonal cold weather, Ülgütol said.

Turkish media reported that security camera footage the police had examined for days led to the discovery of Sierra's body.

Detectives scanned through footage of about 1,000 security cameras to trace her movements and were able to narrow down the last places she visited — they spotted her on the Galata Bridge on the day she disappeared and in the Sarayburnu district where they found her body.

Sierra, on her "dream" trip abroad, was supposed to return to New York on Jan. 22 after two weeks in Turkey. She disappeared after last talking to her family Jan. 21, when she was supposed to meet a man she had been chatting with for months online at Galata Bridge on the Bosporus.

Contributing: Jabeen Bhatti and Ruby Russell in Berlin; the Associated Press