Rights group Amnesty International has criticized a Cameroonian military court after it sentenced three men to 10 years imprisonment for circulating a sarcastic text message about Boko Haram.

The international NGO denounces the non respect of the freedom of expression saying the ruling was “clear evidence” that Cameroonian military courts should not try civilians.

“A judge condemns a person to 10 years in prison on the simple basis of an SMS joke , it is not a terrorist act in view and that Fomusoh and his friends had to denounce it. To make a joke about Boko Haram cannot lead one to serve a 10 year prison sentence,” said Samira Daoud of Amnesty International, Dakar Senegal.

Fomusoh was arrested on December 13, 2014 after forwarding an SMS message to his friends containing a joke about the Nigerian militant group. After being held in a police cell in the western city of Douala, Fomusoh was transferred to the counter-terrorism agency in the capital Yaoundé.

“It is imperative that governments wage war against terrorist groups but they should also protect individuals because it is their duty not to trampleon the rights of citizens“Daoud added.

Daoud said that the ruling was “clear evidence” that Cameroonian military courts should not try civilians and called upon the Cameroonian authorities to unconditionally release all three persons.

“They were simply exercising their right to freedom of expression. Instead of being in school like their friends, these three young men will now spend years of their lives in prison for a simple joke,” she said.

Boko Haram is a militant Islamist group that launched an armed insurgency in north-east Nigeria in 2009. The group has since broadened its attacks to include Cameroon, Niger and Chad.