After seemingly acting so carefully right before and after the shooting I’m perplexed as to why he had so much evidence still on him (Gun/silencer, Fake ID, man

After seemingly acting so carefully right before and after the shooting I’m perplexed as to why he had so much evidence still on him (Gun/silencer, Fake ID, manifesto) during the arrest. One would think he would have discarded or destroyed those things as soon as possible after the incident.