Here is video released by the Sanford, Fla. police department of George Zimmerman reenacting the night that he fatally shot Treyvon Martin:
The first part of the video, up until about 4:55, takes place in a car and you can only catch glimpses of the side of Zimmerman’s face, so let’s jump to 4:55.
5:22- Here we see Zimmerman describe a fact, that the house numbers were not visible because he was behind the houses. This is important because it establishes a baseline, in other words it shows us what Zimmerman looks like when he is telling the truth. One big takeaway is that his “recalling a fact” face has his eyes fixed straight ahead, lids opened beyond neutral and a mostly neutral face with his mouth slightly open.
5:59- Zimmerman talks about his conversation with the dispatcher, and flashes his “recalling a fact” face. So far so good for Zimmerman.
6:49- “…and then they said.” Notice Zimmerman’s “recalling a fact” face again when talking about his conversation with the dispatcher. This serves to further establish our baseline.
8:33- Notice how as Zimmerman is describing his interaction with Martin his head tends to tilt downwards. This is different from our previously established baseline and suggests that he is no longer strictly recalling facts.
8:43- His head is tilted down and then he “pops” up and says “and that’s when I started screaming for help”. He then flashes shame. A deviation from his baseline coupled with the flash of shame and a change in his speech pattern all suggest that we have shifted from truth-telling to lying. The speech pattern change I observe is that in earlier sentences we would say “uh…” and then go into his “recalling a fact” face. In this case he drops his head, his face goes neutral and then he says “uh…”.
My verdict: liar!
I am stopping the breakdown here. It’s difficult, if not impossible, to piece together the truth from this video but I am comfortable concluding that what we’re being presented with isn’t the truth.

You nailed it at 8:43. Obvious liar’s tell… Zimmerman is clearly leaving out important details in this sequence.