Jacob Zuma Must Return to Prison, a Judge in South Africa Rules

 Former President Jacob Zuma of South Africa, who was released from prison on medical parole in September, must return to serve the rest of a 15-month sentence linked to his appearance before a corruption investigation, a judge ruled on Wednesday.

The former president was imprisoned on contempt charges in June after defying an order to appear before a corruption inquiry examining financial scandals that tainted his tenure as the country’s leader from 2009 to 2018. But Mr. Zuma, 79, applied for medical parole within a month of his incarceration and was granted it after being in prison for just two months.

It is not clear when Mr. Zuma will return to prison. The Department of Correctional Services in South Africa said that it was “studying the judgment.”

At the time of Mr. Zuma’s early release, the department said it had been “impelled by a medical report” but offered no further details about the former president’s health. The judgment on Wednesday provided some insight.

Upon being taken into custody in July to begin his sentence, Mr. Zuma was held in the medical wing of a prison near his home in Nkandla, in the rural north of KwaZulu-Natal Province. Within a month, a doctor who examined him described Mr. Zuma’s condition as “worrisome,” pointing to the “unpredictability of his plausible life-threatening cardiac and neurological events.” Another found that his glucose, blood pressure and kidney function had gone “completely out of kilter” after just four weeks.

The medical parole board rejected his application on the basis that his illness was not terminal and could be managed by prison health workers. But Mr. Zuma was released after the national commissioner of correctional services, Arthur Fraser — a political ally of Mr. Zuma’s — overturned the board’s decision.

Nongovernmental groups and the country’s main opposition party, the Democratic Alliance, asked the High Court in Pretoria, the executive capital, to review the move. And on Wednesday, Judge Keoagile Matojane set aside the commissioner’s decision, calling it “irrational” and agreeing with the medical parole board that Mr. Zuma’s health had not “deteriorated permanently or reached an irreversible state.”

The judge dismissed the commissioner’s assertion that Mr. Zuma’s continued incarceration would lead to a repeat of the violence and looting that occurred in South Africa in July soon after Mr. Zuma’s arrest. The unrest, which began as a demonstration calling for his release, quickly gained momentum in protest over broader economic dissatisfaction.

Judge Matojane also ordered that the time Mr. Zuma spent on medical parole not be counted toward his 15-month sentence.

During his time on medical parole, Mr. Zuma released a book, “The Words of a President: Jacob Zuma Speaks,” an account of his administration from his perspective.