The violence that has seized Egypt since late last month is, to many, sadly familiar: Angry young men provoke police, police respond with excessive force. Both sides are counted among the dead and wounded, as are bystanders.
But it was the image of one protester, broadcast live last week, which renewed outrage in a country long used to police brutality.
In the video, 48-year-old Hamada Saber is stripped naked, kicked and beaten by police outside the presidential palace.
At first, after being taken into custody, Saber said it was protesters who beat him. The police, he said from a police hospital bed, had helped him. But Saber later recanted, blaming police for the beating.
Saber's hospital statement brought to mind countless cases of police coercion, part of a larger system of injustice that helped fuel Egypt's uprising two years ago.
“This oppressive apparatus has not changed a bit, at all," said political activist and blogger Wael Khalil. "I mean, it is working with the same rule book. It is still untouchable. No one is accountable."
The interior minister warned that without the police, Egypt could become a militia-state, like some of its neighbors.
But in a rare move from on high, President Mohamed Morsi's office has promised an investigation into the beating.
The president's supporters say there is a sincere drive to overhaul the police.
A senior official of the Muslim Brotherhood's political party, Amr Darrag, said they inherited a system whose role was to protect the government from opposition.
“We are going in the right direction, but still there is a lot for the police force to learn and to get rehabilitated to deal with that,” Darrag said.
But how much influence Morsi has or is willing to use is unclear. Interior Ministry reform has been slow — even as simple a change as emphasizing riot control over confrontation.
One opponent of the president mocked his apparent inability to control the police, in a message on Twitter.
“The only thing worse than a dictator” he wrote, “is a dictator who cannot dictate."
But even as Egypt's police are heavy-handed in some crowds, they are absent in others.
In Cairo's Tahrir Square, violence has increased — in particular, the sexual assault of women by mobs of men. Only civilian volunteers — not police — are trying to protect them.