When the filmmakers were shooting the interrogation scene, in the building next door they came across a German Sheppard guarding the building aggressively. Thinking this dog would be a perfect addition to the search party at the beginning of the film, they cast the dog "Zelda" to appear, but when it arrived, it was so happy to be outside that it did not bark or look menacing at all. The filmmakers opted to only show Zelda for a brief moment in the scene, and recorded audio of it barking while it was back guarding its territory.
Fake murder photos were taken months before principal photography. One of the photo shoots happened in during Easter Sunday in a park, where locals thought it was some ritual, others thought they stumbled on a real crime scene until the filmmakers assured the "victim" was alive and speaking.
Almost no ADR was used, only a few words were rerecorded - the filmmakers proffered the performance of the actors from the location much more and opted to clean up the audio as best as they could.
The dominoes were real, it took 3 days to set up because the first two days they fell over before they were filmed. Other than the scale of the setup, part of the issue was that the dominoes were wooden and made unevenly making them easy to topple. The production wanted a professional domino builder but it was out of the budget, however, the director learned they leave gaps to protect sections as they build it.
The line "remember when Winston took us under his wing? What he taught us day one?... You get a list of suspects and you go knocking on doors, and the one that asks for their lawyer right away you know they did it" - was a line that a real cop told the filmmaker, which he noted and wrote down for future use.