Plot hole: The prosecuting attorney told William, "We've got no video, no photos, no eyewitness except you" and, "Your biggest problem is there is no gun... This case is so paper thin the judge's probably gonna throw it out, and Danny Fetter is gonna be back on the streets... Basically, it's your word against him." William correctly replied, "That's bullshit..." There would still be enough circumstantial evidence (e.g, gunpowder residue, offender placed at the crime scene) to acquire a conviction. (00:10:03 - 00:10:45)
Plot hole: After William told the judge he could not identify the attacker at Kat's murder scene, the judge said, "Mr. Fetter, you are free to go. Case dismissed." The police officer who was assaulted by Danny and other officers should have been present and able to positively ID Danny. Even IF the murder charge could not stick, the other pending charges (assault, possession with intent to deliver, resisting arrest) could still be prosecuted/pled. There was no legitimate reason to let Danny go free. (00:11:10 - 00:11:47)
Other mistake: The plea deal with Danny (5 to 7 years in prison) seems inconsistent with Georgia's sentencing guidelines, recidivist law, and the State's reputation as being tough on repeat offenders. Danny was on parole, which means he was convicted of a felony. His new charges - including assaulting a police officer (an "aggravating circumstance") and possession with intent to deliver - could be enough to impose MAXIMUM sentences or mandatory minimums (10 years?) under sentencing enhancements.
Plot hole: The prosecuting attorney told William "this case [murder of Kat] is so paper thin the judge's probably gonna throw it out" but William could try to convince the D.A. to take it to trial. In addition to circumstantial evidence against Danny and his pending charges (resisting arrest, assault on a police officer, possession with intent to deliver, and parole violations), the random, unprovoked, senseless murder of a teenaged girl would be high profile - such cases are most likely to be prosecuted. (00:09:34 - 00:10:36)
Plot hole: It doesn't make sense for the prosecuting attorney to agree to accept a guilty plea from Danny for assaulting an officer, possession with intent to distribute, and resisting arrest with no accompanying guilty plea for at least a lesser-included offense of murder (such as voluntary manslaughter). A violent gang member committing an initiation murder while out on parole would be dealt with much more harshly, especially when the murder victim was a high-school-aged teenager and random victim. (00:09:34)
Character mistake: The prosecuting attorney told William, "In the interests of getting this thug [Danny] off the streets as soon as possible, his attorney has agreed to plead guilty to assaulting an officer, possession with the intent to distribute, and resisting arrest, and that's all in addition to his parole violations. We're looking at five to seven [years in prison]." The parole violations alone are sufficient to get Danny off the streets immediately. (00:09:34)