Venezuela’s defense ministry announced the death of a navy officer who was accused of participating in efforts to stage a coup against President Nicolas Maduro.

Opposition sources and family members of navy captain Rafael Acosta said he was tortured while in custody of the Maduro regime, Reuters reported Sunday.

Acosta was taken before a military tribunal Friday but fainted before his hearing started, according to Reuters. Acosta was reportedly barely conscious as he stood trial, according to his wife Waleska Perez, who described his situation in an interview with EVTV Miami. He was transferred to a military health center following the trial where he appeared to be distraught, she added.

“They tortured him so much that they killed him,” Perez said.

Acosta was reportedly first detained by Venezuelan authorities June 21, according to The New York Times.

Chief prosecutor Tarek Saab said on Twitter that he would be opening an investigation into Acosta’s death.

Opposition leader Juan Guaido said Acosta was murdered in prison by the Maduro regime.

“Do they not hear? From the grave, from basements where people are being tortured, the people (are calling for) a change,” Guaido said on an internet broadcast, according to Reuters.