A New York City woman who went missing while vacationing alone in Istanbul was found dead on Saturday, and police detained nine people for questioning in connection with the case, Turkey's state-run news agency said.

Sarai Sierra, a 33-year-old mother of two, was last heard from on Jan. 21, the day she was to fly home. Her disappearance attracted a lot of interest in Turkey, where the disappearance of tourists is rare, and Istanbul police had set up a special unit to find her.

The state-run Anadolu Agency said the body of a woman was discovered Saturday evening near the remnants of ancient city walls and that police later identified it as Sierra's.

The agency did not say what caused her death. But the private NTV television reported that she was stabbed to death, while a private news agency, Dogan, said she had a head wound, suggesting she may have been hit with an object.

Police reached by The Associated Press refused to comment on the case.

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 near the bridge and a major road that runs alongside the sea of Marmara. Here tourists often photograph dozens of tankers waiting to access the Bosporus strait.

On Saturday, police stopped traffic there as forensic police inspected the area.

Anadolu suggested Sierra may have been killed at another location and that her body may have been brought to the site to be hidden there.

At least nine people were detained for questioning in Istanbul, and a police official at the site told journalists that two of them are women. The official spoke on condition of anonymity because he was not authorized to speak to reporters about the case.

It was not clear if a Turkish man Sierra had exchanged emails with during her stay in Istanbul was among the nine detainees. 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.

Sierra's husband, Steven, and her brother, David Jimenez, traveled to Istanbul to help search for her. Sierra's mother, Betzaida Jimenez, said on Saturday that she couldn't talk about the case when reached in New York.

Shortly after Sierra was reported missing, Turkey set up a special police unit which scanned hours of security camera footage in downtown Istanbul in search of clues. A Turkish missing persons association joined the search, handing out flyers with photos of Sierra and urging anyone with information to call police.

While break-ins and petty thievery are common in Istanbul, the vast and crowded city is considered relatively safe compared to other major urban centers. Sierra's death was unlikely to have a significant impact on tourism, a large component of the Turkish economy.

In 2008, an Italian artist, Pippa Bacca, was raped and killed while hitchhiking to Israel wearing a wedding dress to plead for peace. Her naked body was found in a forest in northwest Turkey. A Turkish man was sentenced to life in prison for the attack.