One of the things that scares me about the US criminal justice system is that it relies almost entirely on magical thinking and torture to secure convictions. I don't believe anyone is guilty unless they were literally photographed holding the bloody knife while standing over the body and even then I'll need some convincing to rule out potential mitigating circumstances.
My experience with the United States court system, civil and criminal, have convinced me that it operates more or less just like the education and I guess every other system. If you have money and can afford an attorney, you're basically safe outside of something ABSURDLY egregious (if even that). If you don't: get fucked.
Didn't do it? Tough shit you're still going to spend three years in Riker's, lose your job house car and kids, get horrible trauma, and essentially lose everything you ever had and good luck getting back on your feet.