TWO WEEKS AGO I visited one of the most crowded Starbucks branches in Istanbul. My goal was to write a piece on Julian Barnes’s latest essay collection, but while working on the opening sentence about the author’s prominence as a literary essayist, I found myself eavesdropping on a rather curious conversation from the neighboring table. Two baseball-capped men were talking about a missing woman, while carefully and rather nervously looking outside the window. Sitting below the siren logo they were struggling to keep their sights on the endless waves of crowds moving to and fro on the city’s most popular street. It took a few minutes before I realized they were plainclothes policemen. This was followed by a second, more crucial realization: they were looking for Sarai Sierra.

The 33-year-old amateur photographer from New York City was roughly my age. I had been reading newspaper articles about her sudden disappearance with a sense of alarm over the last couple of days. She was last heard from on January 21 and was feared to have been murdered. She took pictures of neighborhoods where I spend most of my time and uploaded them on the photo-sharing platform Instagram. She was taking part in a “#5shotchallenge” designed to “take us out of our comfort zone.” On her Instagram page she had listed rules of this challenge some days prior to her disappearance. “IGer must post 5 pics within 5 days with no posting in between and no reposts,” she wrote. 

Reading about the story in The New York Times, a New York friend called and asked what I thought had happened to her. But like most of my journalist colleagues and the general public, one could only speculate, and I feared the worst. 

Sierra’s husband and children drove to Newark Liberty International Airport on January 22 to meet her, expecting to listen to her tales about Istanbul, Amsterdam, and Munich. Until the day of her disappearance Sierra continued uploading pictures to Instagram. Employed at a chiropractor’s office in New York, she was an amateur photographer who used a Samsung Galaxy 3 and an iPad to take and edit pictures. Most of her work consisted of landscapes or images of deserted social spaces. Her work still remains on Instagram and when I viewed them last week I was left with a desolate feeling. In “Sunset, Istanbul style” the mood is gloomy; “Train station a la Amsterdam” evokes a feeling of anticipation and subsequent disillusionment. The last picture on her Instagram stream, the image of a brook in Holland, is entitled poetically: “Your movement’s similar to a serpent.”

For many of us who looked at those pictures for clues of her whereabouts the crucial question about her fate remained unchanged. More than a thousand police officers were assigned to search for Sierra on Istanbul’s streets. Some newspaper reports argued Sierra was on her way to meet a fellow IGer before her disappearance. The correspondence with this photographer proved to be her last known digital interaction. When Sierra’s husband reported her loss, her landlord in Istanbul said he had no idea where she was. Some people suspected him of withholding information while others insisted the police should keep their eyes on the photographer.

Tarlabasi, where Sierra rented the roo...