As the body of Sarai Sierra made the long trip home to New York, police in Istanbul continued the difficult work of piecing together the details of her death.

Sierra, a 33-year-old mother of two from Staten Island, went missing during a solo vacation to Istanbul in late January and was discovered dead Saturday along the city’s ancient walls—apparently killed by a violent blow to the head. Her disappearance and death have captured widespread attention, inspiring constant news coverage in both Turkey and the United States. Amid the furor, police in Istanbul have been working in overdrive on the case—first in a massive missing-person search and now in the push to find Sierra’s killer.

In an interview with The Daily Beast on Thursday, Ertan Ercikti, the police official who oversees Istanbul’s homicide division, said his detectives are facing added pressure due to the high-profile nature of the case. “We can’t work as freely as we’d like to,” he said. “The people we need to speak with are getting scared away.”

Sierra’s case has promised to be difficult from the start. She was found 12 days after she disappeared, potentially allowing biological evidence to deteriorate. At the same time, Ercikti said, the intense coverage of her disappearance likely put the culprit on guard. The furious speculation surrounding the murder, he added, has proved a burden in itself.

Sitting in his Istanbul office, Ercikti turned up the volume on a TV newscast featuring the latest round—a New York Post article stating that a source familiar with the Sierra case told the paper that FBI agents believe she spent time with a “criminal element” in Istanbul. “I can’t do my job when I have to respond to all these rumors,” Ercikti said, dismissing the claim and adding that police had seen no evidence to support it.

Ercikti then outlined the facts of the case. Sierra was struck in the head with a blunt object, almost certainly the cause of death. She tried to defend herself, and parts of her clothing were torn in the struggle. Her body was covered with a blanket when it was found inside a cavern of the ancient walls, obscuring it from view. Ercikti said Sierra may have been killed nearby, her body then dragged to the spot where it was found, with the intention of hiding it there. It was far less likely, he said, that she had died elsewhere in the city and then been transported there.

“Anything other than this is speculation,” he said.

Police are still struggling to determine a motive. Sierra was found with her earrings and other jewelry intact, but her iPad and smartphone were missing. There coroner’s report will take up to three months to complete, but Ercikti said preliminary findings suggest that Sierra wasn’t raped. Turkish officials have told the Daily News, however, that she was found wearing only a T-shirt and underwear.

It’s unclear whether police are close to finding answers. At least 24 people have been questioned in connection with the case, but none has been detained.

Sierra’s tragic saga in Istanbul did receive one piece of closure Wednesday evening, when her casket began the journey from Istanbul to New York.

Her remains had been resting in an Armenian church in the Beyoglu district of Istanbul, a 20-minute walk from the spot where she was last seen alive. Journalists periodically slipped in to photograph the coffin, then followed as four local men carried it in a somber procession through winding streets to a waiting hearse. The couriers hailed from a local advocacy group for missing persons, and as the hearse pulled away, Celal Sarican was fighting back tears, the event having stirred up the memory of his missing son. “This should never have happened to Sarai,” he said.