Your moving interview with the Colombian academic Miguel ?ngel Beltr¨¢n ("Arrested, beaten, caged - but the state could not break him", News, 5 July) highlights the dangers academics around the world face for speaking out against state violence and social inequality.

Thanks to pressure from non-governmental organisation Justice for Colombia, the academic community and many 51³Ô¹Ï readers, last year the Colombian government dropped the false charges against Beltr¨¢n (it had claimed he was a terrorist) and released him after two years awaiting trial.

As the article makes clear, the academic has paid a heavy price for his freedom and we regret to inform you that his safety remains at risk.

Following serious death threats, Beltr¨¢n has been forced to live and work outside Colombia. However, his employer, the National University of Colombia, Bogot¨¢, recently turned down a request to extend his sabbatical leave (citing his alleged failure to respond to a letter that it claims asked him to provide further details of his activities) and has demanded that he return to campus.

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In the absence of any physical protection being guaranteed by the Colombian state, we are extremely concerned that Beltr¨¢n's life will be in grave danger if he returns to Bogot¨¢.

Our two organisations have written to the university calling upon it to review its decision regarding Beltr¨¢n's sabbatical leave. We urge THE readers to continue to show their support for Beltr¨¢n and other academics under threat in Colombia and elsewhere.

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Mariela Kohon, Director, Justice for Colombia

Sally Hunt, General secretary, University and College Union