The governor of Hatay province said the suspect, identified as Laz Ziya, was nabbed by security personnel in the Reyhanli district of Hatay Sunday.
The accused killed was questioned ahead of an initial court appearance, the governor's written statement said.
Sierra, 33, New York City, disappeared in late January while vacationing alone in Istanbul. Her body was found in early February in the ancient city section, Today's Zaman said.
Notable deaths of 2014 [PHOTOS]