ISTANBUL — The Turkish police searched a Saudi-owned mansion south of Istanbul on Monday as part of the investigation into the murder of the Saudi dissident Jamal Khashoggi, whose remains have not been found.

Irfan Fidan, the chief prosecutor of Istanbul and the leader of the Khashoggi investigation, ordered the search of the mansion, a sprawling building with a columned central portico, set amid trees in the village of Samanli, about 60 miles south of Istanbul. The area, on the Marmara coast, is a popular tourist spot known for its thermal springs.

Police officers searched the area with drones, and forensics officers, a fire brigade and sniffer dogs were at the scene on Monday, Turkish news outlets reported. The newspaper Hurriyet said that the mansion belonged to a Saudi businessman, and that it had been unoccupied for the past month. A second house, adjacent to the mansion, was also being searched, Hurriyet reported.

Mr. Fidan’s office issued a statement Monday afternoon saying that the search was conducted because one of the Saudi suspects in the Khashoggi case had contacted the occupant of the mansion the day before Mr. Khashoggi was killed, and the conversation may have been about disposing of his body.