A former mayor of Tehran who once served as one of Iran’s vice presidents has been sentenced to death in the killing of his wife, state news outlets reported, in a case that has been closely watched in the country.

Mohammad Ali Najafi, 67, the former mayor and a prominent reformist politician, was arrested in May after turning himself in to the police. His case made waves after Iran’s state broadcaster showed footage of him at a Tehran police station, sipping tea and smiling with police officers as he confessed to killing his wife, Mitra Ostad, 35.

A spokesman for the judiciary said he had been convicted of murder and sentenced on Tuesday to “qisas,” a term meaning retaliation in kind — a decision handed down as part of the country’s Islamic judicial system, according to the semiofficial news outlet Tasnim.

Because Mr. Najafi’s wife was killed, that would amount to a death sentence in his case. His lawyers could not be immediately reached for comment, but they told Iranian news outlets that he would appeal the verdict.