I've been looking for Avis' policy on late returns. For late returns, they basically continue to charge the card plus a daily $10 fee, and at some point the missing car is looked for. But I couldn't find a determinant timeframe. In one case, a non-returned car was gone for 7 months (and out of state) before the rental car company took action. Perhaps Enrique's credit card should be reported stolen so charges can't continue against it.
However, it's possible he has a secret credit card and is paying for the rental, so there is no mystery or crime (from Avis' perspective). I'm not sure if they have privacy policies that keep LE from finding this type of info out without a subpoena.
My gut instinct says this guy had a car accident. Maybe he decided to take a drive after not being able to get a flight.
FAQ for Avis rentals
https://www.avis.com/en/customer-service/faqs/usa/rental-policies
Cross Border Rentals
Taking a car across a state border is generally not a problem. However, it's always best to inquire about any restrictions or fees that may apply if dropping the car at a different location. Inquire either at the location or simply contact us.
Into Canada:
With advance arrangement and consent from Avis, certain cars may be rented from the United States and driven into Canada by U.S. residents. A Canadian non-resident insurance card may be required and is available at the Avis rental location.
Into Mexico:
Driving U.S.-owned cars into Mexico is always prohibited.
Forms of Payment
Avis does not require a deposit to reserve a car. However, an Avis honored charge card must be presented at the time of rental. Acceptable charge cards are as follows:
Avis Charge Card
American Express
AT&T Capital
China Union Pay
Diner's Club International
Discover
GE Capital
JCB
MasterCard
Sears
Visa
Split Billing Option:
Avis also offers a split billing payment option which provides billing flexibility. Customers may split their rental charges on two separate credit/debit cards. In addition, corporate customers have the ability to charge counter products, optional services that are not covered as a company expense to a personal credit card. Customers who wish to split their rental charges on two separate credit/debit cards can choose to split the rental charges by one of the following ways: