The killing of a young Tehran woman at the hands of her high-profile husband, an ally of the Iranian president and a former mayor of the capital, has riveted the nation, dominating headlines and social media chatter.

Mitra Ostad, the younger second wife of Mohammed Ali-Najafi, reportedly died 28 May of gunshot wounds in a rare instance of gun violence in urban Iran.

Mr Najafi, a former mayor of Tehran who currently holds several official titles, turned himself in to police and, in a surreal twist, confessed to the killing in a television interview.

The killing, which unfolded in the upmarket Saadatabad district of the capital, has dominated newspaper headlines, broadcast news, and social media feeds.

Mr Najafi, 67, claimed he killed his 36-year-old wife in a domestic dispute. She was killed with bullet wounds to the heart and arm, according to local media.

“Today as the arguments of the last two or three days escalated, I became quite angry, I brought the gun,” he said in a television interview with the state broadcaster.

“She went into the bathroom, I went after her mostly because I wanted to scare her. I showed her the gun and I said 'do you want to end the argument or not?' She panicked and jumped on me.”

The case raises issues about the country’s Iranian elite power dynamics, as well as prevalent violence and discrimination against women. It also raises questions about the role of state media, a tool of hardliners which has in the past been criticised for normalising violence against women. It broadcast an interview with a couple earlier this year in which a man confesses to beating his wife and preventing her from divorcing him for decades, as his spouse says she has forgiven him.

At one point on Tuesday, a state TV reporter held the alleged murder weapon in a live appearance, and emptied the bullets out of the magazine, noting that out of 13 rounds five had been fired off.

The case could damage the reputation of Iran’s reformists, who are allied with President Hassan Rouhani, and embolden hardliners who have long depicted their rivals as morally corrupt.

“Shooting at the heart of reforms,” blared the headline on the front page of the hardline Vatan newspaper.

“Tehran in shock,” read the headline in Arman, a reformist paper. “Bitter fate of a technocrat,” was the headline of the reformist Sharq.

Mr Najafi, a graduate of the Massachusetts Institute of Technology, is a member of Iran’s reformist faction, and as Tehran mayor was seen as a potential national political contender. Hardliners hounded him out of office last year after attending a celebration that featured dancing young girls, which hardliners described as not in keeping with strict Islamic rules that forbid interaction between men and women.

Mr Najafi turned himself in to authorities voluntarily, police told state news. "Our colleagues at the Police Criminal Investigation Department met Mr Najafi  a few minutes ago. He came and explicitly admitted killed the aforesaid woman,” Brig Gen Ali Reza Lotfi, Tehran police chief, told state TV. “The gun with which he committed the act was discovered too. Now my colleagues are investigating and interviewing Mr Najafi in cooperation with judiciary officials."

It remains unclear what motivated the apparent discord between the couple. The news outlet Ensaf reported that Ms Ostad had contacted them earlier in the week to schedule an interview about Mr Najafi and their marriage. She was killed before she could conduct the interview.  The semi-official ILNA news agency quoted Mr Najafi as telling the court that an unnamed state institution was eavesdropping on his conversations and passing the recordings on to his wife, stoking her anger and suspicions.

Mr Najafi was shown on television being treated with deference and sitting down amicably with police officials, a courtesies  rarely granted dissidents and alleged criminals who are arrested.