They talk about the note, it was to a loved one, passcode to phone, wasn't a suicide note per se. Bank information, passwords, etc.
There was a firearm in the Subaru. It was a long gun rifle. No word on what weapons were found on RC.
Motive? Clearly a mental health motive, waiting to get access to those records for further information. Based on interviews, there doesn't appear to be any forcible committed mental health treatment for RC, which is why there were no yellow flag or background checks that would have helped prevent this. Only involuntary commitments trigger yellow or red flag laws or affect background checks.