Academic freedom is a cause held dear by most scholars, but very few will suffer for it as Miguel Angel Beltrán has.
However, the Colombian sociologist did not set out to become a role model for dissident intellectual thought, let alone spend two years in a high-security prison for his beliefs.
In May 2009, Dr Beltrán was spending a sabbatical working as a postdoctoral researcher at the National Autonomous University of Mexico when he attended what he thought would be a routine immigration check.
However, after signing a document, two guards burst in, handcuffed him and covered his head. He was then bundled into the back of a van and taken to an interrogation room.
"My face was covered and they forced me to crawl under a chair. Then they beat me," Dr Beltrán recalled in an interview with Times Higher Education.
"There was no arrest warrant or charges. I was held for seven hours, unable to contact anyone, and then put on a plane to Colombia.
"The next day, the Colombian president [Álvaro Uribe Vélez] went on TV to say they had captured one of the country's most notorious terrorists."
So what had this softly spoken researcher done to warrant arrest, torture and extradition?
The reason related to a rocket attack on an Ecuadorian village a year earlier, which had claimed the life of Raul Reyes, leader of the Revolutionary Armed Forces of Colombia (Farc).
In the wreckage of the blast, a computer was recovered, which was said to contain two research papers written by Dr Beltrán while he was working at Bogota National University.
The papers, published in the university's main journal, examined the changing role of student protest in Colombia and whether the Farc movement was an insurgency or simple terrorism, Dr Beltrán explained.
"These were articles published openly - anyone could access them," he added. "The authorities claimed one of the articles was an incitement to violence. There was no evidence, but they claimed I was participating in fundraising for Farc."
Welcome to hell
Dr Beltrán was thrown into Bogotá's notorious La Picota Prison, where he spent the next two years awaiting trial.
"They put me in with paramilitary prisoners, drug traffickers and violent criminals," he said.
"When state employees are held for trial, they are normally held separately. I was denied this right."
The academic had been very critical of paramilitaries in his writing, often speaking out against their human rights abuses, so his "life was in great danger".
"I was held in a 3m-by-4m cell with five or six other people. There [was] no proper sanitation, the food was terrible and people often got sick because they were so close together," he said.
The academic added: "My son was born when I was in prison and they would not let me see him. They wanted to break me."
Salve of solidarity
Dr Beltrán was acquitted of all charges in June 2011, but he left Colombia and has been unable to return after his family received death threats.
Despite this, he is still employed by Bogota thanks largely to the support of his union, the Asociacion Sindical de Profesores Universitarios (Aspu), and is a vocal critic of Colombia, where critics claim that 3,000 trade unionists have been murdered since 1986, including several academics.
In his first visit to the UK since his release last year, Dr Beltrán received a standing ovation as he addressed the University and College Union congress in Manchester last month.
He was keen to thank the British lecturers who wrote to him and campaigned for his release alongside Justice for Colombia, a coalition of 40 national trade unions campaigning for change in the country.
"There were moments [when] every door seemed to be closing. But that solidarity meant I did not feel alone," he said.
"It gave me dignity and the strength to carry on."