Revealing mistake: The visiting nurse was using a non-functioning sphygmomanometer to take Dan's blood pressure. On-screen, the nurse compressed the air inflation bulb about 10 times without the gauge (measuring unit) moving. The nurse compressed the bulb about 10 more times - a ridiculously high number (about 20 total) - but it could not be seen if the gauge ever moved. (02:11:10)
Revealing mistake: The coroner was made to appear as though he took another bite from his donut, but when he was lowering the donut from his mouth the bite pattern on the donut had not changed. (00:03:48)
Continuity mistake: Dan set his lighter on top of the pack of cigarettes with their bottoms flush, but a close-up showed the lighter at an angle with one corner protruding past the bottom of the pack of cigarettes. (00:04:52 - 00:05:28)
Audio problem: It isn't clear what the woman was saying while she was kissing Frank, but it would not have been possible for her to be vocalizing any words while her lips were on Frank's. When they were done kissing, her last word did not match her mouth movement. (01:28:10)
Revealing mistake: After Jess leaned her bicycle against the pole, it slid down onto the ground. In subsequent views of the bicycle to Jess' side, the bicycle appeared to be upright and not what would be expected if it was lying on the ground. The height of the bicycle's seat should have been closer to the chair's arm, not Jess' shoulder. At a different angle before Jess got up, the bicycle was positioned like it was right after it slid onto the ground. (01:04:02 - 01:05:47)
Other mistake: The view of Katherine's bloody body showed blood running diagonally almost exclusively from left to right, but the Ten Killer slashed her equally from right and left. Blood should have run in both directions. (00:45:05 - 00:46:25)
Other mistake: The "Ten Killer" slashed Katherine Hourback's face/head close to 50 times (off-screen), leaving her face covered in blood. When Dan found Katherine's body in his front yard, there was diluted blood on her face (mostly left side), but no indication that she had been slashed with a utility knife about 50 times. Also, during the slashing, the Ten Killer's "aim" seemed off (too high for a victim sitting in a chair and with no adjustment for how her head might move after each forceful blow). (00:45:05 - 00:46:53)
Continuity mistake: The fourth time Jess raised the cigarette to her mouth, it was about half the length that it was 5 seconds earlier; cigarettes don't burn this fast. (00:47:45)
