Continuity mistake: While the mother is driving her children to school in a minivan, both the driver's seat and the front passenger seat change from having the headrest/whiplash protector being attached to the seats (non-removable), to having the adjustable kind that have been removed.
Continuity mistake: When Charlie is in his office talking to Larry, while going over the potential killers and victims, he writes the word "Killers" on the board and circles it. Then, when Charlie notices that Larry has left and says "gone", the writing is different. The 'k' is wider, and most noticeably, the left side of the circle is gone, and the loop in his 's' disappears. Once Charlie goes back to working, the word changes back to how it was originally written. (00:38:20)
Visible crew/equipment: After Charlie tells Alan that he and Amita have a lot of work to do and that Alan's hovering over them, when Alan walks away from the table we can see the actor's tape marks on the floor where he had been standing, and also more blocking tape on the rug and kitchen floor.
Continuity mistake: While Don's at the parking garage with Rachel Abbott's car he realises that the killer had been watching Karen Silber's house, and when they rush off to her house there are white security bars on the windows and front door in the long shot and also later in the news footage, but when they're at her house none of those bars exist and the shrubbery also differs.