When Peter drives in his car just before he enters the crime scene by the diner, in the car he wears a three-days beard, when getting out of the car throughout the scene at the crime scene the beard is gone, and after that in the sheriff's car the beard is there again.
The clock on the wall in the sheriff's office is not running.
The waitress, in signing the "mix" CD with a black felt tip pen, signs the wrong side of the disc; an obviously unburned, blank CD.
The waitress removes a CD that she has supposedly just burned. Impossible as she has inserted the disk upside down as can clearly be seen as the disk compartment ejects the disk.