I had a Dodge Dakota that while driving it all the gauges pegged and everything came on that wasn't already, pulled over had it towed to the nearest dealer and when they looked at it said the CPU was bad and had never seen a bad one before, the whole thing, not just components. so they had to order the part as it was non-standard and didnt carry one, even at a truck dealership. Got it, put it in, viola! it's fine. It was covered by the warrenty but I beleive I had low miles.
If you have 20,000 and it is not covered then I would have them write a statement explaining they think it is lighting, explain why you can rule out the tow truck driver, and submit it to your insurance, lightening should be covered. you'll have to pay a deductible but it wioll be far lower.
Also what are the chances someone tried to hotwire it frying the electrical in an attempt to disable the security?