In glimpses and in glaring detail, the videotape images reveal the robust presence of disguised officers or others working with them at seven public gatherings since August 2004.

The officers hoist protest signs. They hold flowers with mourners. They ride in bicycle events. At the vigil for the cyclist, an officer in biking gear wore a button that said, "I am a shameless agitator." She also carried a camera and videotaped the roughly 15 people present.

Beyond collecting information, some of the undercover officers or their associates are seen on the tape having influence on events. At a demonstration last year during the Republican National Convention, the sham arrest of a man secretly working with the police led to a bruising confrontation between officers in riot gear and bystanders.

Until Sept. 11, the secret monitoring of events where people expressed their opinions was among the most tightly limited of police powers.

Source:
NYtimes.com