During the chase of the dirt bike the Charger police car turns from an early model with square taillights to a newer model with racetrack taillights in the alley at the end of the chase.
During the opening chase scene the front license plate of Ray Archer's car disappears, then reappears.
At 1:51 in the foreground is a woman in tan pants carrying a bag and tall coffee. The chase is in the background. Again at 2:00, the same scene is shown with different editing, but background chase goes by again.
In the train scene, Christi's scar is on the wrong side of her forehead and slanted in the wrong direction.
In the mausoleum scene where Jimmy was streaming live with the camera, he threw it on the floor when talking to Archer. A moment later as the police in the station are watching the feed, her face was clearly shown level which would be impossible from the camera on the floor.
When Al Pacino mentioned the food dye stamp on the pigs head, he stated " The FDA stamps pig heads with a code number in case of disease." The stamp is true, but the FDA works only processed or adulterated food products; not fresh meat products. This is the job of the USDA, United States Department of Agriculture.
When Det. Archer took the watch off the 2nd victim at the Coroner's office and handed it to the Coroner. He asked the Coroner to dust it for prints. That would be the job of the Police forensics at the crime scene. They also would have bagged it and entered it into evidence way before the Coroner even got the body.
The Honda motorcycle is actually a dirt bike with a headlight in the chase scene.
When Ruiney and Archer have their idea to check a list of criminals whom they had arrested, an officer tells them they arrested a few dozen the previous year but only 5 were released from prison in time to have committed the hangings. Yet Ruiney and Archer immediately consult the full list and find Adam Kellerman's name, rather than looking at the reduced list of the 5 potential suspects. When they ask the officer to pull up Kellerman's profile, at this point the list of 5 suspects comes onto the screen, rather than Kellerman's profile.
Dispatch calls Detective Ruiney to Bancroft Elementary where he finds a body, but later while talking to Detective Archer, he refers to it as Wayward Elementary.
Dr. Westlin repeatedly issues a cause of death as asphyxia with only minimal examination of the bodies. While it might be clear the victims were hanged, a doctor will need a more thorough examination to be certain what an actual cause of death was--for instance, someone could have had a heart attack while being hanged. Further, hanging can result in more than one specific cause of death. For instance a doctor would need to distinguish between oxygen deprivation due to a person being unable to breath, and due to arteries leading to the brain being cut off. While a doctor or coroner might be willing to offer police preliminary ideas, they would not speak as absolutely as Dr. Westlin did about a cause of death.