Cuban dissident Danilo Maldonado, known as “El Sexto,” was arrested Dec. 25. (Alejandro Ernesto/EPA)

A jailed graffiti artist whose case became a rallying cry for opponents of the Cuban government was abruptly freed Tuesday after 10 months behind bars, according to Amnesty International.

Danilo Maldonado, known as “El Sexto,” was arrested Dec. 25 while riding in a taxi en route to an art show. Cuban security agents searched the trunk and found two live pigs that Maldonado was planning to set loose, painted in garish colors with the names “Fidel” and “Raúl” on their backs.

The planned performance, meant to evoke George Orwell’s “Animal Farm,” never happened. Maldonado, 32, was accused of disrespecting Cuba’s leaders, but he never faced formal charges, according to Amnesty International. He was the only Cuban activist left on the group’s list of “Prisoners of Conscience.”

The list once carried dozens of Cuban names, but in recent years the government has opted to use short-term arrests and detentions to disrupt attempted protests by the island's small opposition groups.

“Danilo’s release is great news but he should have never been jailed in the first place. Peacefully expressing an opinion is not a crime,” Erika Guevara-Rosas, the Americas Director at Amnesty International, said in a statement.

“This long awaited positive move must open the door for much needed political reform in Cuba, where people are routinely harassed, arrested and thrown in jail on spurious charges for speaking their minds,” Guevara-Rosas said. “This needs to change urgently if Cuba is serious about respecting human rights, including the rights of people opposing the Cuban government.”

There was no statement from Cuban authorities, but they consider activists such as Maldonado to be paid lackeys for the U.S. government and Miami exiles trying to bring down the Castros’ socialist system.

Maldonado’s cause was championed by international rights groups and Cuban American lawmakers such as Sen. Robert Menendez (D-N.J.), who argued that his imprisonment was proof that President Obama’s engagement policy has failed.

Before landing in jail, Maldonado was not a well-known figure among Castro opponents, but the simple, cursive graffiti tag “El Sexto” was a common sight in several Havana neighborhoods.

While in jail, Maldonado refused to eat for several weeks. He ended his hunger strike this month after Cuban authorities said they were considering his release.

Maldonado told the Reuters news agency that guards at the Valle Grande prison instructed him to gather his belongings on Tuesday morning and that he was set free within 30 minutes.

“Now I am going to try to recover my energy and be with my daughter,” he told Reuters. “I want to travel to the United States in the future and thank all the people who supported the cause to have me freed.”

Maldonado was taken into custody just eight days after Obama and Cuba’s Raúl Castro announced their plans to reestablish diplomatic relations and work toward full normalization. As part of that deal, the Cuban government agreed to release 53 inmates whom the United States considered political prisoners.

Cuba insists that it has no political prisoners. The illegal-yet-tolerated Cuban Commission for Human Rights and Reconciliation, a Havana dissident group that keeps its own tally of jailed activists, said it has about 70 names on its list, but they include airplane hijackers, militants and others convicted of violent attacks.

Obama has urged Cuban leaders to embrace democratic reforms and broader tolerance for dissent, saying that is key to building support in Congress for ending U.S. trade sanctions imposed by the Kennedy administration 55 years ago.

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