In October, Iran confirmed the arrest of British-Iranian anthropologist Kamil Ahmadi before releasing him, and in December it freed Xiyue Wang, a Chinese-American researcher serving a 10-year term on spying charges
Authoritarian governments in the Middle East are increasingly willing to seize researchers and academics, who are seen as valuable bargaining chips in their joustings with Western nations, analysts warn.
"The risks now facing researchers in the Middle East are unprecedented," said Jean-Pierre Filiu, a historian at France's Sciences Po University.
Filiu was speaking on Friday at a forum dedicated to two French colleagues, Fariba Adelkhah and Roland Marchal, who have been imprisoned in Iran since their arrest last June.
They have been charged with conspiracy or collusion against national security, while Australian Kylie Moore-Gilbert of the University of Melbourne is serving a 10-year sentence on espionage charges.
Often authorities target their own citizens who have dual nationality, like Adelkhah, with Tehran in particular refusing to recognize a second passport.
In October, Iran confirmed the arrest of British-Iranian anthropologist Kamil Ahmadi before releasing him, and in December it freed Xiyue Wang, a Chinese-American researcher serving a 10-year term on spying charges.
Wang was released in exchange for Masoud Soleimani, an Iranian who had been held in the US for allegedly breaching sanctions - and Tehran said it was open to other such exchanges.
But over the decades, the targeting of academics has often been more violent.
"It started with gunshots at the office of Malcolm Kerr, president of the American University of Beirut, who was murdered in 1984 by Hezbollah, already an arm of the Revolutionary Guards" of Iran, Filiu said.
Two years later, French sociologist Michel Seurat died in a Lebanese prison after his arrest because he was "denied medical care," he said.
"They were victims of the settling of scores by Iran with Washington and Paris."
Eyes on the ground
More recently, Italian doctorate student Giulio Regeni disappeared in Egypt while researching trade unions, one of the country's last independent civil actors - and increasingly in the crosshairs of the authorities.
His badly mutilated body was found more than a week later by the side of a road on the outskirts of the Egyptian capital, with an Italian post-mortem later indicating he had been tortured.
And in May 2018, British researcher Matthew Hedges was arrested in the United Arab Emirates and held in solitary confinement for months before beginning a life sentence on spying charges.
He was released less than a week after his sentencing - and just as the United Nations dropped a UK-sponsored resolution demanding a halt to the UAE and Saudi Arabia offensive in Yemen.
"Mr Hedges may be their bargaining chip to get London to back off from a UN resolution calling for a halt to the war in Yemen," Mark Almond, director of the Crisis Research Institute at the University of Oxford, wrote in The Telegraph newspaper a few days before his release.
"Miraculously the stars aligned, and his release finally came as the British initiative was abandoned," Filiu agreed.
Yet analysts say the crackdown on academics comes as on-the-ground research becomes increasingly vital for understanding the political and socio-economic dynamics in play across the Middle East.
Threats from jihadist forces as well as the rise of nationalist and authoritarian tendencies are prompting officials to severely restrict access to outsiders.
Iran in particular is holding "10 to 15" foreigners including Nazanin Zaghari-Ratcliffe of the Thomson Reuters Foundation, who is serving a five-year term on charges of sedition, Jean-Francois Bayart of France's CNRS research institute told the forum on Friday.
His colleague Bernard Hourcade, a geographer and Iran specialist, blamed a new generation of Republican Guard elites who grew up in an "ostracized republic."
"Many of them have no international experience. They don't speak French, English or German," Hourcade said.
"If today Fariba and Roland are in prison, when normally you take diplomats or business executives hostage, it's because they were trying to see what's really happening," he added.
"These people are panicked by the idea that people would know what's going on in their country."
According to Filiu, "access is increasingly denied by powers and organisations which know perfectly well that the research can help counter the lies and propaganda used to sow terror among their own peoples."
Washington's killing of the Revolutionary Guard commander Qasem Soleimani last month, and Iran's own accidental downing of a Ukraine airliner, has turned up the heat on Tehran.
But even if Iran appears more vulnerable, "they are not necessarily in any position to negotiate or make any offers," said Olivier Roy, a specialist on Islam at the European University Institute in Italy.
Hence the temptation, analysts say, to keep a handful of foreign researchers behind bars.