A "perpetual motion machine"..?
Inventor Stan Meyer was said to have created and demonstrated a water powered car that could cross the continental US with 20 some gallons of water and no gasoline. Later courts ruled that he was lying.
On March 20th, 1998, he was eating at a Cracker Barrell in Ohio with two potential investors. In the middle of the meal he ran outside, fell to the ground, said, "They poisoned me," and died.
Authorities found no foul play.
Wikipedia says he was a fraud, of course.
Wikipedia is a good place to start your research perhaps but almost never the place to end it.
Who killed the electric car?
Perhaps the question could be who killed the water powered car?
Perhaps the question could also be who killed Stan Meyer?
Perhaps no one.
Perhaps someone who makes money off gasoline.
Perhaps someone who profits from the greater society working an extra day out of the week to pay for energy, electricity, power that we could be getting without the trouble of oil extraction, processing, and transportation (which is to say someone that profits from the masses being more distracted than necessary). Is that not what Nikola Tesla was pointing at with he zero point energy devises? A different technology perhaps, with a similar outcome.
There is a lot out there about him that you can find on your own, but here is a Car Throttle article, if you are curious.
With much respect and curiosity,