ANKARA, Turkey (AP) — Turkish authorities are investigating the death of an American author and journalist who died while traveling overnight from the Turkish Black Sea coastal city of Samsun to Istanbul, Turkey’s state-run news agency reported Tuesday.

Andre Vltchek, 57, and his wife were traveling inside a rented and chauffeured car and arrived in front of their Istanbul hotel at around 5:30 a.m. on Tuesday. His wife tried to wake him up to tell him they had arrived but could not do so, the Anadolu Agency reported.

Medical teams called to the scene declared him to be dead, the agency said.

The Istanbul chief prosecutor’s office immediately launched an investigation into the death, while his body was taken to a forensic medicine institution to be examined, Anadolu reported.

The private DHA news agency said police recorded his case as a “suspicious death.”

On his website, Vltchek described himself as a novelist, philosopher, filmmaker and investigative journalist as well as a “revolutionary, internationalist and globetrotter who fights against Western Imperialism and the Western regime imposed on the world.”

He covered dozens of war zones and conflicts, including in Iraq, Sri Lanka, Bosnia, Rwanda and Syria, according to his website.

Vltchek authored numerous books, including “On Western Terrorism: From Hiroshima to Drone Warfare” with linguist and scholar Noam Chomsky.