Adil Oksuz is said to be the civilian leader of air force personnel loyal to the Fetullah Terrorist Organization (FETO), which was behind the July 15, 2016 putsch attempt.
Speaking at a news conference in Ankara, Kalin said Turkey was expecting the German authorities to investigate the issue seriously:
"First of all, our demand is, of course, that the German authorities start the necessary procedures to extradite that person [Oksuz] to Turkey from the moment that he was seen in Germany."
On Wednesday, Foreign Minister Mevlut Cavusoglu also asked Berlin to investigate the media reports saying: "As the Foreign Ministry, we issued a diplomatic note to Germany.”
Last week, Turkish newspapers claimed Oksuz had been seen in February in Frankfurt and Ulm by Turkish residents.
The Yeni Safak newspaper reported that he had applied for asylum in the southern state of Baden-Wurttemberg.
The theology professor is alleged to be the “imam” to FETO members in the air force and a key link between U.S.-based FETO leader Fetullah Gulen and coup plotters in Turkey.
Both Oksuz and Gulen are being tried in absentia in a case involving 486 defendants accused of helping orchestrate the coup bid from Akinci air force base, north of Ankara.
Oksuz and another defendant, businessman Kemal Batmaz, were reportedly caught on camera returning to Istanbul from the U.S. two days before the attempted takeover. The authorities say they had visited Gulen in Pennsylvania to discuss the plot.
Both men were arrested near Akinci on July 16 but Oksuz was released and then disappeared.