VIENNA, Austria — Austrian authorities recovered a Stradivari violin belonging to a top violinist and worth at least $3.4 million after police raided a Vienna house used by six Georgian suspects to stash stolen loot.

“We’re just happy to be able to return the instrument to our star violinist in undamaged condition,” Interior Minister Günther Platter said at a press conference yesterday in the Austrian capital. He returned the 327-year-old instrument to Christian Altenburger, a violin soloist who has played with the London, New York, and Vienna symphony orchestras.

The Georgian gang was involved in at least 21 other house robberies in Vienna and had stolen jewels, art, and liquor, police said. The Stradivari, along with a Vuillaume violin, were stolen from Mr. Altenburger’s apartment in May. The two instruments were displayed together in a green velvet-lined leather case in a ceremony after the press conference.

Police found the suspected thieves after they tried shipping some of the stolen goods in a suitcase taken from Mr. Altenburger’s apartment. Postal authorities alerted the police, who followed suspects to an apartment, which was subsequently raided yesterday. Austrian authorities are continuing to investigate the breadth of the crime network, Mr. Platter said.

“It was like finding a needle in a haystack,” said investigator Margit Wipfler, adding that a fingerprint on the stolen suitcase was the key clue to solving the case.

Antonio Stradivari made violins in Cremona, Italy, until his death in 1737. There are fewer than 700 known Stradivari violins in the world, according to the Cozio Web site, which identifies and assembles prices for old stringed instruments.

“I’m very happy and relieved,” said Mr. Altenburger. “I didn’t think it would happen so quickly.”