In the bright morning hours of 28 October, a busy square in an affluent area of north-west Tehran became the scene of a bloody murder.
This was no ordinary crime. It was more like a public spectacle, dragging on for an excruciating 45 minutes before the victim bled to death.
At least two armed police officers and hundreds of spectators stood by while the assailant continued to torment the victim and threatened to commit suicide if anyone intervened.
These facts of the case, sensationally picked over by the media, have sent shockwaves through Iran - with ordinary people, as well as the authoritarian state, questioning the response.
Caught on camera
The entire episode was recorded on mobile phones and the footage was promptly posted on the internet.
It shows the victim, a 30-year-old man later identified in court documents as Yazdan, lying on the road in a pool of blood, after being stabbed multiple times.
He is heard begging for help from bystanders: "For the love of God, call emergency services, I am dying."
But he was only taken to hospital after his attacker - named as Yacoub - left the scene.
Doctors pronounced the victim dead, but said his life could have been saved if only he had been brought in 10 minutes earlier.
While the details of this case were still being absorbed, more amateur video came to light on YouTube showing an earlier murder also carried out in full public view.
In that video clip, a middle-aged woman stabs a man repeatedly in a busy street while a police car and later an ambulance watch on from a safe distance.
The scene looks so calm, it is almost surreal. At one point, the attacker returns to her home unchallenged and emerges after a while, having put on the customary long Iranian coat. She then proceeds to stab the motionless victim a few more times.
The apparent indifference of witnesses to both gruesome murders has prompted national soul-searching and been analysed in-depth by Iranian sociologists and intellectuals.
Not so long ago, Iranians took pride in their collective sense of responsibility and compassion. It was normal and expected that people would intervene to try to defuse any public altercation.
Not any more it seems. In the video from October, lurid comments can be heard while shop-keepers joke and sip mugs of tea as they watch the attack on their doorstep.
Another matter is the apparent ineptness of the police at both scenes.
Iranian officers are armed and have shown a readiness to resort to lethal force when dealing with unarmed opposition protesters. After the disputed presidential elections, at least 30 protesters were killed in clashes with the security forces.
Now many critics are suggesting that the Iranian police are exclusively tasked with securing the state rather than preventing crime and providing a safe society for the public.
With such allegations engulfing the Persian blogosphere, these incidents have become an embarrassment for the Islamic state.
A police commander accused foreign media of tampering with the footage of the female murderer until it was traced to a crime in the city of Karaj, to the west of the capital.
The prosecution of the Tehran murderer was sped up by the authorities so that it was brought before an extraordinary court within three weeks.
The murderer, who described his motive as rivalry over a woman, was sentenced to death by public hanging with sources in Iran suggesting he will be hanged in the very square where the murder was committed.
This outcome has added another issue to the ongoing debate around the incident.
Supporters of Sharia law have long argued that the Islamic law of retribution is intended to serve as a deterrent to potential criminals.
Public hangings have become relatively common. The execution of Shahla Jahed, the mistress of a prominent footballer for the murder of his wife last week was reported to have been the 146th in Iran this year.
However, some opponents believe that such punishments have desensitised Iranian society to violence.
They claim it has instead inadvertently legitimised its use and fermented social apathy towards acts of violence.
The circumstances of these murders caught on tape, they say, epitomise the dangers.