“I think that we, opponents, are not having our best moment,” Ms. Roque said.
Human rights advocates say that Cuba has about 100 political prisoners and that the number of arbitrary detentions each month dropped by nearly half after Mr. Díaz-Canel took office in April 2018. But that decline, Mr. Vivanco said, largely reflects the fact that there are fewer dissidents remaining in Cuba to be detained.
Mr. Ferrer and three colleagues were arrested on Oct. 1 and accused of kicking a man in the head until he lost consciousness. Mr. Ferrer’s friends and family say that they have proof the man was hurt in a motorcycle accident despite what they call fabricated witness testimony to the contrary.
Nelva Ortega said Mr. Ferrer, her husband, was beaten and lost a great deal of weight during the 25-day hunger strike, which he began after becoming convinced that he was being given contaminated food and water, and has since ended. He refused to wear a prisoner’s uniform and was left naked for weeks, Dr. Ortega said. She claimed that he had lost half his body mass, but was unable to take any photographs to document it.
“The water that came down from the roof is what they were giving him to drink,” Dr. Ortega said in a telephone interview a few days after her first brief visit with him. “The food looked like it was ready to be thrown out, like the food you would give to pigs.”
In a letter to the United Nations, the Cuban government said that accusations of torture were lies.
But Alan P. Gross, a former contractor from Maryland who spent five years in prison in Cuba, said that although the notion that Mr. Ferrer lost half his body weight was probably an exaggeration, it was customary for prisoners to be fed meals infested with ants or roaches.
“I lost 70 pounds by the time my case went to trial,” Mr. Gross said. “I thought Díaz-Canel would be better, because he wasn’t part of the family, and he never really had a military background.”
The president, he said, is probably not fully in charge, given that Raúl Castro is still head of the Cuban Communist Party.