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The discovery of a New York woman's body in Turkey has done little to solve the mystery surrounding her disappearance and death, say sources involved in the international investigation.

Sarai Sierra, a 33-year-old mother of two from Staten Island, N.Y., traveled to Istanbul on a solo vacation Jan. 7 and failed to return on a flight Jan. 21. Her body was found Saturday near remnants of the city's ancient walls. But many of the questions that surfaced during the search for Sierra -- such as whom she contacted, why she took two side trips and where she stayed -- remain unanswered.

Turkish authorities say Sierra died from a single blow to the head. A local funeral company on Tuesday told the Hürriyet Daily News, an English-language newspaper in Turkey, that she had multiple injuries to her head and face.

"There are serious blows, particularly to her head and face," Manuel Manukyan, owner of the Nevzat funeral company, told the newspaper. Manukyan is working with the U.S. Consulate and Sierra's family to bring her remains back to the U.S.

Prosecutors in Istanbul got a court order Monday for authorities to take blood and DNA samples from 21 people already questioned in the death, according to Turkish state media.

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    Sierra, a freelance photographer, was found in the clothes she was last seen wearing the day she disappeared, authorities said, noting that there was no sign of a sexual assault. Sierra's jewelry was still on her, but her tablet computer and U.S. cellphone were missing.

    Samples reportedly taken from under her fingernails suggest she may have tried to fight off her attacker. A blanket was also found near the body, leading investigators to question whether she was killed in another location and then placed near the ancient walls, which are close to a highway.

    Turkish authorities finished an autopsy Monday on Sierra and gave DNA samples from it to a crime lab, the state-run Anadolu Agency reported. After that, Istanbul prosecutors got the court order but did not identify the possible suspects, the agency reported.

    A source familiar with the investigation told FoxNews.com that it is believed Sierra contacted "amateur tour guides" online to show her around popular sites in the city. Sierra's trip also included pre-planned excursions to Amsterdam and Munich. Authorities, however, have said little about those trips, which, combined with her expenses in Turkey, are said to have cost more than $10,000, according to the Hürriyet Daily News.

    New York Rep. Michael Grimm, a former FBI agent, said Turkish police still have hours of video footage to review as they piece together Sierra's last movements. A special unit of Turkish police set up to find Sierra has an image of her at Galata Bridge, which spans Istanbul's Golden Horn waterway and where she went on her last day to take photos. An FBI official confirmed to FoxNews.com that the agency is also involved and has been since the early stages of the investigation.

    Meanwhile, her family was working out how to return her body to the U.S.

    "Our No. 1 priority right now is bringing Sarai home," Grimm said during a press conference Monday with Sierra's family in Staten Island.

    Sierra's husband, Steven, is in Istanbul, where he traveled last week to help in the search. He intends to accompany her body back to New York, but the family is still determining how to fund the transport. Their church and friends are working to raise money to help defray the costs.

    Sierra made her first trip overseas alone after her childhood friend, Magdalena Rodriguez, backed out. At Monday's news conference in New York, Rodriguez fought back tears as she said she wished she had not changed her plans.

    "I wasn't working at the time and I didn't have the money to go," she explained.

    Sierra's two sons, ages 9 and 11, have not yet been told of their mother's death, according to family members.

    "We're going to talk about that when he gets back," the woman's mother, Betzaida Jimenez told reporters Monday.

    She recalled hugging her daughter before she departed and praying together for a safe journey.

    "Just the thought that I'll never be able to hug her again," she said, pausing to compose herself. "We just didn't think a tragedy like this was going to happen."

    FoxNews.com's Cristina Corbin and the Associated Press contributed to this report.