Ursula Lindsey profiles them:
Part of the problem is that the powers that be have made it a policy to keep policemen violent, dependent, and corrupt. They are badly paid, badly trained, and threatened with early retirement or a court-martial if they disobey orders, says Mahmoud. The real responsibility lies with the higher-ups in the ministry, he argues, who earn fat salaries and make all the decisions.
Lindsey follows up at the Arabist:
It is the leadership of the security forces that is responsible for cultivating the police force's hostility towards the revolution — policemen are angry (ashamed and afraid too, I think); they feel they have lost the "respect" of society, because they can't imagine a respect that isn't founded on unaccountable power.