A NASA physicist has been arrested in Turkey in the aftermath of the failed 15 July coup, according to Turkish media outlets and evidence from multiple sources. Serkan Golge, a 36-year-old US citizen of Turkish descent, is accused of involvement with the Gülen movement, which president Recep Tayyip Erdoğan holds responsible for the attempt to overthrow the government.

Golge arrived in Turkey in late June to spend time with family. According to a source who wishes to remain anonymous, Golge was accused of spying for the CIA by a person in the neighborhood where the family lives. Over the past month, Erdoğan and other government officials have accused the US of supporting the attempted coup. Ercan Topaca, governor of the Hatay province in southern Turkey, announced the arrest to the state-run press agency Anadolu on or around 6 August.

serkan gölgeA US State Department official said the agency is aware of reports that an American citizen was detained in Turkey but would not comment further due to privacy concerns. Other State Department contacts told Bill Jones, chair of the Turkey coordination group at Amnesty International USA, that the consular section in Turkey is aware of the case and working on it. The University of Houston, which employs Golge through a contract with NASA, confirmed that he has missed work.

Jones says he knows of no other reports of American citizens detained in Turkey since the failed coup. Golge has been a US citizen since at least 2010; it’s unclear whether he also has Turkish citizenship. The Turkish Embassy in Washington, DC, did not respond to multiple requests for comment.

Golge’s colleagues at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, where he performed his graduate and postdoctoral research, say they have not heard from him since 20 July. Alicia Hofler, a computer scientist at Jefferson Lab, says Golge wrote that he was in Antakya, the provincial capital city of Hatay, but hoped to return to the US on 24 July. Last week, after not receiving responses to several emails, Hofler searched for Golge’s name online and saw a tweet and news reports about his alleged detainment.

Golge is accused of spying for the Fethullahist Terror Organization, the Turkish government’s designation for the Gülen movement, according to Topaca’s reported statement. Topaca also noted Golge’s schooling in Turkey. Golge received his bachelor’s degree in physics from Fatih University in Istanbul, a Gülen-sponsored school that was shut down by the Turkish government following the coup attempt. “If he attended Fatih, that may well be sufficient evidence in the eyes of the government,” Jones says.

Some 82 000 academics, judges, civil servants, and other professionals have been suspended, fired, or arrested since 15 July, Jones says. The country’s paranoia that the CIA or other US players supported the unrest has put “any American visiting Turkey during the time of the coup at risk of being rounded up as a conspirator,” Jones says. Under the current state of emergency, Turkey can detain suspected plotters without charging them with a crime. It’s unclear whether Golge has been formally charged.

Golge traveled to Turkey about once a year to visit family, Hofler says. His wife and two sons, a six-year-old and a four-month-old, flew to Turkey along with his parents on 1 June. Golge joined them on 26 June, flying into Atatürk Airport in Istanbul two days before the terrorist attack there that killed at least 45 people. He wrote to Hofler on 16 July, hours after the failed coup: “We are OK. Unfortunately, everything is upside down.”

Since 2013, as a senior research scientist at NASA’s Johnson Space Center in Houston, Golge has studied the effects of radiation on astronauts aboard the International Space Station. He has helped create models that predict the risk of cancer from galactic cosmic rays and has analyzed data from particle detectors on the space station. At Jefferson Lab he worked on the PEPPo experiment to generate polarized beams of positrons.

Hofler and her colleagues have contacted organizations including the State Department and the American Physical Society’s Committee on International Freedom of Scientists. Carol Valoris, executive director of the Committee of Concerned Scientists, sent a letter on 16 August to Vice President Joe Biden, who is scheduled to meet with Erdoğan in Turkey next week.

This article originally appeared in Physics Today on August 16.