The instrument, built in the mid-1700s, is insured. But its owner, described as a "prominent musician" living in Washington, considers it priceless.
There were no signs of forced entry to the car. Tow truck manager Marco Aure protested his innocence. "Why would we take anything? We're good people," he told KGO-TV.
Nakajima had been hoping to buy the violin. "It's as if you know you have the perfect life partner. It's as if I found someone like that," she said.
Nakajima told police she regrets not parking the car in the local garage, "I would have spent only nine dollars at the parking garage instead of a $175,000 mistake." Her wallet and iPod were also stolen from the car.
Violin shops nationwide have been informed of the theft.