The police failed to read his Miranda rights and performed an illegal search when arresting him. One officer began to search his bag when another officer told her that she needed a warrant to do it. She repacked the bag, turned off her bodycam, then 11 minutes later turns it back on and continued to search it without a warrant:

Patrolwoman Wasser continued her warrantless search of the backpack. Patrolwoman Wasser first re-opened the same backpack compartment that she had started searching at the McDonald’s before immediately closing that compartment and opening the front compartment of the backpack as if she was specifically looking for something. Instantly, she “found” a handgun in the front compartment.

The cops planted the gun. Of course its a “ghost gun”, super convenient that it’s impossible to prove whether or not he owned it. Guess we just have to take the cops good word on it 🙄 and the entire point of one is to ditch it at the scene or shortly afterwards without risk, so it makes no sense that he still had it on him. Luigi doesn’t look like the shooter in any of the other videos or pictures. The whole story of him being caught doesn’t make sense, either. The shooter put in a great effort to escape while remaining untraceable, but then was randomly found, with no leads or connections, hanging around in public at a mcdonalds, literally carrying around a confession and the gun, instead of lying low??? Oh come on, if you wouldn’t believe that garbage as the plot of a crime show on TV, it’s reasonable doubt. He’s innocent. The end.

https://gizmodo.com/luigi-mangiones-legal-defense-fundraiser-tops-1-million-2000598676

https://cdn.sanity.io/files/detu0qji/production/1b9e211bd3c7770699b4244c4e9bc5074498ee82.pdf