Danilo Maldonado Machado, the Cuban graffiti artist known as “El Sexto,” remains in prison to serve at least 60 days for his public celebration of the death of Fidel Castro on the streets of Havana. Maldonado has snuck a letter to the Cuban people out of prison, urging them to “demystify” the “murderer” Castro.

“The Cuban people march by force under the sun and shout slogans like ‘I am Fidel,’ but many are silent because the Cuban people fear, and with fear one cannot be free,” Maldonado’s letter — published on Facebook by his Miami-based girlfriend Alexandra Martínez — reads.

“So long as people keep their heads bent down with a miserable salary, with nothing to eat, emigrating, and demanding the exterior what we are not capable of demanding as human beings here — freedom — incidents like what they are doing with me will keep being the norm in Cuban society,” he writes.

“We must learn to demystify a murderer, because if not, that day [that Castro dies], nothing will happen,” he continues. “What will be my daughter Renata María’s future if we keep worshipping murderers?”

“The true and only enemy of the Cuban people is the occupation of the Castro brothers,” he concludes.

Maldonado was arrested on November 25, 2016, after he took to the streets of Havana to celebrate the announcement of the death of dictator Fidel Castro. The artist spray-painted the words “he’s gone” on a wall and recorded a Facebook Live video of himself celebrating and urging passersby to cheer the dictator’s death.

Maldonado is facing charges of defacing public property, which his mother says only legally require him to pay a 100-200 peso fine. Instead, Cuban authorities told Machado that he will remain imprisoned for 60 days. “A lawyer has taken on his case but all that is so that nobody says we are not taking care of Danilo,” his mother told the Spain-based Diario de Cuba. “Everyone knows that this is a State Security process, that Danilo is unjustly imprisoned… we are awaiting the results of the habeus corpus challenge,” she said.

“Remember he is an artist, that he has not taken up a weapon, that what he uses is a brush and spray, he rises against the government with his painting,” she tells the outlet. “He is a pacifist.”

Machado, who is the only individual known to have been able to interact with Maldonado, told international outlets that Maldonado had been stripped naked, beaten, and kept in solitary confinement this weekend to prevent him from observing International Human Rights Day from prison. Maldonado told his mother he had not been fed in three days.

“On Friday, Saturday, and Sunday, they kept him in solitary confinement, totally naked and without food, because they suspected he was going to protest for the December 10 International Human Rights Day,” she told Diario de Cuba. The artist had told his mother previously that he was refusing to eat prison food because he suspected they had laced the food with sedatives, to prevent him from shouting “down with Fidel” and “down with Raúl” from his prison cell.

His first week in prison, Maldonado was beaten so severely that the beating triggered an asthma attack. He was beaten again for demanding medical attention during the asthma attack, he told his mother.

“When I saw him I felt my heart shrink,” Machado, his mother, told the Miami news agency Martí Noticias. “But I will be firm, nobody will see me cry, if I cry nobody will know.”

“He wants everyone to know he is a pacifist, his body is imprisoned but his mind is free,” Machado said.

Maldonado is one of several Cuban dissidents arrested in the aftermath of Fidel Castro’s death. The Cuban Commission for Human Rights and National Reconciliation (CCDHRN), an NGO that tracks politically-motivated arrests on the island, estimated that at least twenty individuals have been arrested for opposing communism following the elder Castro’s death.

While some were arrested for openly celebrating the death, like Maldonado, many were arrested to prevent such a display, particularly dissidents known to live near the route for the procession carrying Castro’s alleged ashes.

Others were not arrested but brought in for questioning. Among them LGBT rights activist Nelson Gandulla Díaz, who told the outlet Cubanet that secret service agents “threatened me, they told me that if I continued my pro-LGBT Cuban activities they could not vouch for what would happen to me or my family.”