(NEW YORK) -- Sarai Sierra, the New York mother who disappeared in Turkey while on a solo trip, took several side excursions out of the country, but stayed in contact with her family the entire time, a family friend told ABC News.
Turkish media reported Monday that police were trying to establish why Sierra visited Amsterdam and Munich. Police were also trying to establish the identity of a man Sierra, 33, was chatting with on the Internet, according to local media.
Rachel Norman, a family friend, said the man was a group tour guide from the Netherlands and said Sierra stayed in regular touch with her family in New York.
Steven Sierra, Sarai's husband, and David Jimenez, her brother, arrived in Istanbul Monday to aid in the search.
The men have been in contact with officials from the U.S. consulate in the country and plan to meet with them as soon as they open on Tuesday, Norman said.
After that, she said Sierra and Jimenez would meet with Turkish officials to discuss plans and search efforts.
Sarai Sierra was supposed to fly back to the United States on Jan. 22, but she never showed up for her flight home.
Her two boys, ages 11 and 9, have not been told their mother is missing.
Sierra, an avid photographer, left New York on Jan. 7. It was her first overseas trip, and she decided to go ahead after a friend had to cancel, her family said.
"It was her first time outside of the United States, and every day while she was there she pretty much kept in contact with us, letting us know what she was up to, where she was going, whether it be through texting or whether it be through video chat, she was touching base with us," Steven Sierra told ABC News before he departed for Istanbul.
But when it came time to pick her up from Newark Liberty International Airport in New Jersey, Sierra wasn't on board her scheduled flight.
Steven Sierra called United Airlines and was told his wife had never boarded the flight home.
Further investigation revealed she had left her passport, clothes, phone chargers and medical cards in her room at a hostel in Beyoglu, Turkey, he said.
The family is suspicious and said it is completely out of character for the happily married mother, who met her husband in church youth group, to disappear.
The U.S. Embassy in Turkey and the Turkish National Police are involved in the investigation, WABC-TV reported.
"They've been keeping us posted, from my understanding they've been looking into hospitals and sending out word to police stations over there," Steven Sierra said. "Maybe she's, you know, locked up, so they are doing what they can."
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