In Agent Jackman's dossier, a still grab of Piper from the episode "A Paige From The Past" is seen. The picture is taken from the jewelry store surveillance video that Darryl and Piper removed to conceal evidence of the crime committed by a possessed Phoebe and Cole. Since the surveillance video tape had been taken and subsequently destroyed, it would not be possible for Agent Jackman to have obtained the still-shot for his file.
Piper tells the Angel of Destiny the last time they came across a being that could freeze time, it was a demon. Besides the fact that they have never come across a demon that could freeze time (Tempus could manipulate it, not freeze it) Piper herself can freeze time and should not be so easy to believe that a being with her power is evil.
The girls can't use their powers to save Selena because of the amulets that Jackson buried yet Cole is able to use his powers to save Phoebe when Jackson shoots his gun at her. His powers shouldn't have worked either.