Rudy Guede is the murderer. His DNA and fingerprints were found everywhere. The crazy thing is, the Italians let him out of prison in 2021, only serving 13 years for murder.
Lumumba was the bar owner where Knox worked. He texted her that she wasn’t needed that evening, and she replied saying she would see him later (a very American English expression). But with intense questioning (in Italian only, a language Knox had only a limited grasp of), the Italian police insisted it meant they had met up that very night in the apartment, and thus could have been involved. With the stress of the questioning, Knox eventually agreed. Essentially, it was 100% the police’s fault Lumumba was falsely accused.