CAIRO: One of the more disturbing aspects of life in Tahrir Square over the past few days has been the crowd's periodic detention of men believed to be plain-clothes police officers.
Egypt's Interior Ministry is notorious for the number of plain-clothes thugs on its payroll, and most Egyptians are suspicious at the best of times.
But since several thousand pro-Mubarak demonstrators tried to break the anti-government protesters' hold on Tahrir Square on Wednesday, using live fire, petrol bombs and rocks, an element of paranoia has taken hold among those in the square.
Someone points the finger at anyone who looks remotely suspicious and within seconds the mob reacts. The man at the centre of the picture (at right) was one such unfortunate individual.
He was identified several hundred metres north of the square, past the Egyptian National Museum, which can be seen in the top left corner of the picture, and was detained.
The arrest went like this:
One member of the crowd grabbed the man's arm and yelled: ''Here is a policeman. I recognise him. He is a police officer.''
Three or four men then jumped on him and wrestled him to the ground. Soon enough someone was holding up an ID card.
''Yes,'' he screamed. ''This proves it. He is a policeman.''
Inspecting it myself, the ID card looked like any other Egyptian ID card. There was nothing on it to indicate that this man was a policeman.
''You're not looking at it properly,'' someone said, trying to suggest that relevant detail was hidden in the card's holographic image.
Word that a policeman had been caught spread so quickly that within seconds a cluster of 50 had formed around the man, with people jumping over each other to kick, punch or beat him.
In this case, someone held up a penknife several centimetres long - further proof in the eyes of the crowd that the man was an enemy agent - and the beatings became even more severe.
''Traitor, traitor, traitor,'' the crowd chanted. Whenever the man managed to put up his head to protest his innocence, he only made himself more of a target.
The pattern with such men has been to drag them to the southern end of Tahrir Square and detain them in a makeshift prison where they can be handed over to the military later.
While the beatings look severe, and the expression on the face at the centre of such a mob is always one of pure fear, so far no one has been lynched.
But surely it is only a matter of time.