Originally Posted by dieselmania

Block heater fires are not that uncommon, we have had probably half a dozen threads on them over at the Powerstroke forum in the past year. The PSD heater is 1,000 watts, which makes for more current than on the Benz heaters.
Also 7.3 Superduty trucks (99-03) are in such demand that resale value is higher than Blue Book value most eveywhere, and they are easy to sell on top of it, no reason to torch one.

Add to that, if someone wants to get rid of one just park it on the street for a few nights, it'll disappear.

I'd say it's a pretty big stretch to say it was arson.