So, it's pretty wide open? Not that this would prove anything, but if there is regular commercial activity in his home town (meaning; he's using credit cards, banks, ATMs, etc.) then he suddenly drops off the record for 10 days, that would be telling by itself.
I'm sure (okay, not) that the Boulder DA has gotten his bank records to look for large cash withdrawals just before the murder...
WOuld they still be available after 10 years?
Business record....HIS own bank records might show nothing....OTOH. If he's a drug mule, it may be cash under the table....Pick up the car and the drugs at the same time. Careful not to put the money in any account.