Innocent Or Guilty?

[Aeritai]

On what grounds would you arrest him? What crime do you think he committed, and what's your probable cause?

This is a small-town police department as mentioned in the OP. Why do we need to have any of that?

Even if it's a small-town police department, they still need to act professional like their city counterparts.

[Ethel mermania]

On what grounds would you arrest him? What crime do you think he committed, and what's your probable cause?

This is a small-town police department as mentioned in the OP. Why do we need to have any of that?

In the US the county would provide the resources if the town can't afford the extra detectives or labs.

[The Two Jerseys]

Ask him to come to the station and make a formal statement while forensics tosses the house. Since it doesn't sound like he has anyone to verify his alibi, hold him for 48 hours while you get a warrant for his phone records.

That's about all you can really do within the law.