Sarai Sierra is seen in this handout photo.

An American tourist whose body was found in the ruins of Istanbul’s old city wall was murdered by a blow to the head, the city’s police chief was quoted as saying on Sunday.

The husband of Sarai Sierra, 33, from New York, identified her body late on Saturday at an Istanbul morgue, state broadcaster TRT reported. She had been travelling alone when she was reported missing on Jan. 21.

“It’s certain she was killed by a blow to the head,” police chief Huseyin Capkin was quoted as saying by CNN Turk television.

Police are investigating the possibility that Sierra was killed elsewhere and her body moved to Sarayburnu, the area where she was found. Officers are questioning 11 people, media reports said.