Continuity mistake: Near the end of the movie when Alex walks from the room at the end of the hall following Wyatt's voice in Katie's house she sees Katie at the end of the hall. Katie charges at Alex and breaks though the door, forcing Alex to jump from the window. If you watch Katie, her shirt starts out black when she is running down the hall to immediately turning white when she breaks through the door. (01:22:00)
Continuity mistake: While Ben and Alex are on their way out the back door her jeans are grey. At the play house they are blue. (01:27:00)
Continuity mistake: When Alex and her boyfriend are going up to the play gym, her hair style changes. It's crimped as they are walking up, then changes to straight when they are taking Hunter home.
Revealing mistake: When Wyatt is in Katie's house we can hear him call his sister's name, however he says Kathryn, which is the actress that plays Alex's real name.
Answer: Maybe seeing the dead body in the closet prompted her to grab her camera in case she needed evidence to show the police who had killed her boyfriend and possibly her father. There is enough time between shots that it is possible she calls the police from her cell while grabbing the camera.
oddy knocky