"I doubt it'd be shipped out that quickly to some far-off place," Robert K. Wittman, founder of the FBI's National Art Crime Team, told the Milwaukee Journal Sentinel Tuesday.
Frank Almond had just completed a performance Monday at Wisconsin Lutheran College when he was attacked in the parking lot with a stun gun and robbed of the 300-year-old instrument, Milwaukee Police Chief Edward Flynn said.
The robber took off with the "priceless" instrument in a maroon minivan, Flynn said.
"The artistic heritage of Milwaukee was assaulted and robbed last night," he said.
Chicago violin dealer Stefan Hersh said the violin, known as the Lipinski violin, was comparable in value to another Stradivarius that sold for more than $3.5 million in a 2006 auction.
But because the violin can only be appreciated by a very small portion of the population, it's unlikely to sell "for even a fraction of its value," Flynn said.
"These are wildly valuable to a tiny slice of the art world," he said.
Wittman said such pieces are usually stolen by someone with "stars in their eyes" over the value but the suspects rarely think about how they will be able to sell the piece.
"They do a good job with the crime but never really think about what they're going to do with the item," he said. "They get stars in their eyes from the values, but the values for these types of things depend on authenticity, history and a good title -- you have to own it, and they don't."
The violin was on loan indefinitely to Almond from its anonymous owners, the Journal Sentinel reported.