ANy logical conclusion of the evidence at most suggests a high level of reasonable doubt over her guilt, and most of the evidence simply doesn't support her being guilty.
The lead prosecutor has previously tried to blame murders on satanic cults, he has been convicted of lying under oath, and is just a whack job, no where else in the world but Italy would he still be able to try cases.
Her interrogation was a 30 hour ordeal with people on record as hearing a scream, and she claims to have been hit. They didn't provide her with a lawyer and the "interpreter" as a police man who interpreted whatever he liked, false confessions in such circumstances aren't rare, she didn't understand or speak italian very well, and was asked to GUESS what happened several times.
The threesome theory, made up by the prosecutor to make her look bad, a drug addict and taking lots of things, they only found weed in her system... a drug fuelled rage on weed.... is an incredibly rare thing, jealous of a girl who is clearly not close to as attractive as her? THe threesome stuff, drug stuff, and trying to make the jealousy case is all stuff that people love to look down on people who like sex, take drugs and they wanted to make the prosecution point out that their client was more attractive than a dead girl, it looks bad to say so, its a lie that is hard to disprove without making their client look bad, something "dodgy" prosecutors do.
The person still in jail for the murder INITIALLY admitted to doing it ON HIS OWN, after being pushed himself, he named to accomplices and in doing so, got a lesser jail term than he otherwise would have gotten. His DNA was all over, and IN Kersher. He clearly did it and from the outside it looks like the prosecutor had their "big" case with the american girl and was in the press and had gone after the probably wrong people, so after a short while the guy who at first admitted he did it himself.... suddenly changed his story to implicate others and take some of the heat off himself?
Evidence wise the police refused to break Kersher's door IIRC to start with, left the apartment unlocked, had dodgy witnesses, blamed DNA on Knox even though her DNA would be all over the apartment anyway. Supposedly it was a few drops of blood in the bathroom, when you go home, if you spot two drops of blood in the kitchen or bathroom, is your first thought "someones been murdered" or someone had a nosebleed or something, do you stop your life because of a nose bleed? If the entire floor is covered in blood, you check if everyones okay, a couple drops of blood, no.
Could she have done it/been involved, for sure, thats pretty much the answer to almost anyone who is close to a murder and the question lingers over a huge portion of people who get found not guilty of murder... but reasonable doubt, the case is full of it.
Italian law, is a joke, italian police, lawyers, politicians, the entire system, is an entire joke. One of the biggest criminals in the country is the guy who ran the damn thing for years.
The interogation was dodgy as hell, and could EASILY have been done right, they chose to do it stupidly and not get a proper interpretor or independant witnesses. They chose to not lock up the apartment, and "found" evidence days later in a completely unsecured crimescene, even the evidence that the break in was done after, was after the girls room had people go through it to check it, I believe it was basically glass on top of(and underneath) stuff in the room, usually glass hits the floor and then when you throw stuff about its only on top of the glass. But as other people went in, more glass could have been knocked around, quite easily.
Trials a joke, unfortunately when a trial/evidence/investigation/interogation are so profoundly screwed up there is little chance of finding the truth, and certainly no way anyone should be put in jail for donkeys years. One guy is still in jail, the only person to ADMIT killing the woman, at first he admitted he did it on his own. He's by FAR the most likely killer, the rest is the Italians trying to save face by putting someone else in jail so they can claim a win... unfortunately that isn't just an Italian thing, "justice" around the world is more about winning than the truth these days.