Istanbul police today detained a man who exchanged online messages with Sarai Sierra, the American tourist who disappeared Jan. 21, reports the AP. The man was brought in for questioning before police decided to arrest him, but they would not provide any additional information about him or the reason for his arrest. According to Turkish media, Sierra had planned to meet the man at a bridge she wanted to photograph on the day she disappeared; that was also the day of her flight home, which she never checked into. It's not clear whether the meeting at the bridge took place. (More Sarai Sierra stories.)