Local government councillor Bothwell Pasipamire said four Zimbabwean secret policemen took him away from his family just after midnight on December 13. and that he was beaten and humiliated at what he described as a torture camp.
No officials were immediately available for comment, but President Robert Mugabe’s government has repeatedly rejected allegations of torturing opponents.
Pasipamire described himself as a victim of what the opposition MDC says is a widespread campaign of violence against its members despite the September 2008 power-sharing agreement between party leader Morgan Tsvangirai and Mugabe.
"Two men confronted me, one put a gun to my neck and they told me to walk with them," Pasipamire told a news conference in Johannesburg, South Africa, where he fled after escaping.
He said his wife ran to their vehicle to try to stop them taking him away "but the man with the gun shouted: ‘Go back to your house now (or) I will kill you’."
Pasipamire said he spent three days locked up in Goromonzi, about 32 km (20 miles) east of the capital Harare. There was no independent confirmation of the details of his account.
Pasipamire said two men in their 30s who seemed "bored with their work" took him for interrogation at about 6 a.m.
He was asked why he did not support Mugabe’s ZANU-PF party.
His answers angered them. They were then joined by an army warrant officer he described as "a sick man with a sick mind".
After accusing the MDC of blowing up trains, the warrant officer beat the soles of his feet, he said.
"It seemed he was trying to embarrass me in front of the other two who were still in the room. He would fondle me like a lover, and then suddenly squeeze my testicles so that I cried out in pain," he said.
Despite his own pain and humiliation, it was the chilling sound of men shouting "mother help me" in the local language from nearby cells that horrified him, forcing him to wrap his blanket around his head to try to keep out the sound.
"I cannot properly tell you how terrible it is to be cold, wet, unable to sleep and surrounded by the sounds of men crying in pain. This was the worst torture of all and will be with me all my life," said Pasipamire.
Pasipamire said he and 23 others he did not recognise were brought out of their cells and hosed with water.
He said he was also filmed confessing to killing army soldiers and being trained as a guerrilla in Botswana, which has been highly critical of Mugabe.
Pasipamire angrily recalled his answers, shouting.
"My scripted answer was, yes I was trained in Botswana. Yes I was given orders to kill soldiers," he said.
Zimbabwean intelligence officers helped him escape, said Pasipamire. He said he would not give details to protect them.
Pasipamire said he may have been detained because as a councillor he rejected an application by a ZANU-PF member to obtain 10 hectares of land. He has little hope of returning to Zimbabwe soon and now says opposition leader Tsvangirai should not join a government with Mugabe.
"Mugabe is clinging to power," he said.