Milwaukee Police Chief Edward Flynn said the violin was recovered from a suitcase in the attic of a Milwaukee residence overnight Wednesday.
The violin appears to be in good condition, he said.
Citizen tips to police and the Milwaukee Symphony Orchestra and information about the stun gun used in the theft led to the arrests of three people, Flynn said.
Two men, ages 41 and 36, and a 32-year-old woman are in custody, according to prosecutors.
Flynn said one of the suspects has a previous art theft conviction.
"It appears we had a local criminal who had an interest in art theft and was smart enough to develop a plan for a robbery," the chief said. "Beyond that, we don't know what his motive was."
The instrument was taken from the orchestra's concertmaster, Frank Almond, in a brazen attack outside Wisconsin Lutheran College on Jan. 27.
Almond was walking to his car after a performance at the college when someone jumped out of a van, shocked him with a stun gun and seized the Stradivarius, which was on loan to him. The robber got back into the waiting vehicle, which sped off.
The violin was crafted in 1715 and has been appraised for insurance purposes at $5 million.
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