CARACAS - Venezuela’s defense ministry on Sunday confirmed the death of a military officer who opposition leaders and family members said was tortured in custody after his detention over alleged involvement in a coup plot against President Nicolas Maduro.

The death of navy captain Rafael Acosta came on the heels of a visit by the United Nation’s human rights chief Michelle Bachelet to investigate rights violations ranging from extrajudicial killings to forced disappearances.

Maduro last week said military officers, with the support of opposition politicians and foreign political leaders, had plotted to overthrow his government.

Acosta was taken to a military tribunal on June 28 but he fainted before the hearing could begin, the defense ministry said in a brief statement on Sunday, leading the judge in the case to transfer him to a military hospital.

“Despite providing him with the appropriate medical attention, he died,” the statement said.

The U.S. State Department accused Maduro’s government of torturing Acosta to death.

“This is not the first time the Maduro regime has used violence against its political prisoners,” State Department spokeswoman Morgan Ortagus said in a statement.

“The United States calls on the democracies of the world to join us in condemning this latest violation of human rights and in applying pressure to achieve accountability against the aggressors.”

Acosta was barely conscious in a court hearing on Friday after having been beaten and tortured, his wife Waleska Perez said in an interview with a Miami television station, based on information she said she received from Acosta’s defense counsel.

“They tortured him so much that they killed him,” Perez said in an interview with EVTV Miami from Colombia.

The information ministry and the state prosecutor’s office on Saturday night both issued statements about Acosta’s death, but neither described the cause of death.

The information ministry did not immediately respond to an email asking whether or not Acosta had been tortured.

Venezuela’s security forces have come under increasing scrutiny for arbitrary detentions, inhumane conditions of detainees and inadequate investigation of torture allegations.

Political leaders and rights groups last year accused authorities of torturing opposition politician Fernando Alban and throwing him from a window after he was detained in connection with an attack on Maduro. The government called his death a suicide.

Maduro says the country is unfairly targeted for criticism by foreign governments, and insists that his administration investigates and prosecutes human rights abusers.

Former intelligence chief Manuel Christopher, who joined a failed April 30 uprising against Maduro and later fled the country, in a letter on Sunday called on military commanders to “join the side of those in need and stop crossing your arms while our people and our soldiers are killed and tortured.”

Christopher was deputy director of military intelligence agency DGCIM until last year. Acosta’s family and human rights advocates accuse the DGCIM of having tortured Acosta, and the group is described by local rights organization Provea as the state security agency most involved in torture in 2018.

A phone number listed on DGCIM’s website was not functioning. The defense ministry, which oversees DGCIM, did not respond to an email seeking comment.

The ruling Socialist Party has overseen a devastating economic collapse of a once-prosperous nation. Maduro says the country’s problems are caused by sanctions imposed by the Trump administration.

Opposition leader Juan Guaido, who in January invoked the constitution to assume a rival interim presidency, said Acosta was murdered and that was further evidence that Maduro’s allies refuse to heed demands for a change of government.

“Do they not hear? From the grave, from basements where people are being tortured, the people (are calling for) a change,” said Guaido in remarks broadcast over the internet.