Here you've got zero property damage, no victim, no ID of driver (just car), and the car is now on in the guy's driveway and he's home. What on earth can you "find" to tow the car? And when you tow the car and the guy walks out of the house (an hour later then when he parked if you're fast) what do you do? FST? He doesn't have to consent to that or breath or blood as he's not driving. And the illegal seizure of the property won't poison absolutely everything after that in the case?
Now there are two posts with easy criminal case tossed and good civil case ramifications. I'd say unbelievable but as I'm doing more criminal work now I believe every bit of it.
As far as the initial post, sorry, man, nothing else you can do but call when you see it and hope driver is caught while still driving. (and No way that other car was a cop).
I may not be explaining myself very clearly likely because this is a shorthand post and not a report that needs all the info.
Of course it's not the perfect scenario but about 95% of drunks I run across aren't thinking clearly (duh). So yes, they will come to the door, come outside, do FST's, whatever. Did he have to? No. Did he consent? Yep, thus negating any of your objections. And it's on video and audio. Mr. Cobalt (a victim of assault with a deadly weapon) or the OP can ID them (first question to both and if they can't the guy is off the hook). I don't work in the sticks so response times are fast. I can have a tow truck in as little as five to ten minutes to tow a car that was involved in a crime (ADW). I don't have to see them driving, even the DMV admin per se forms have an area to include a private citizen as the witness to driving.
Then the DA will offer the guy a deal if it's his first offense (3 years probation, ignition interlock device in car, DUI classes) and I won't even go to court. In fact I haven't been to court on over 100 DUI's in the last two years and a check of the cases shows them being filed and convicted.
So, I'd get my conviction and your civil complaint would never make it to trial after our City Attorney finished with it.
You are right though. An hour later he comes out? No dice. No witness to ID the driver? No dice. No answer at the door? No dice.
Goes right along with: I am still surprised when I read a suspect Miranda information and they admit the crime to me. 90% of people do and they have all seen enough TV to know they shouldn't. Goes back to my theory that people are generally honest and good or want to be.