The instrument, built in 1742 by Sanctus Seraphin, was on loan from the Mandell Collection of Southern California. It had been left on the passenger seat of Deutsch's car while she shopped at a Los Angeles-area grocery store.
"I saw the window was open before I got to the car, and I just had this horrible feeling," Deutsch said. "I knew it was gone. To lose it and to know it's out there but not to know where it is is really painful for me."
The 20-year-old Deutsch has appeared as a soloist with the New West Symphony, California Philharmonic, and other ensembles, and on the public radio program From the Top.