One person was arrested in connection with the theft, police Lt. Ron Iizuka said.
Police Chief Don Pedersen said the break in the case came when the suspect pawned one of the guitars at a Hollywood pawn shop for $250.
"Mr. Petty would have joined us, but he's preparing for a concert in Denver," said Pedersen, who described the stolen guitars as collectively worth $100,000.
A message seeking comment from the band's publicist, Jim Merlis, was not immediately returned.
The instruments were reported stolen Thursday from The Culver Studios, a sprawling complex of soundstages west of downtown Los Angeles where Tom Petty and the Heartbreakers had been rehearsing for an upcoming tour.
The instruments were Petty's blond 1967 maple 12-string Rickenbacker and his Gibson SGTVJunior, Mike Campbell's blue Dusenberg, Ron Blair's Fender Broadcaster and Scott Thurston's 1967 Epiphone Sheridan.
On its website, the band offered a "no questions asked" $7,500 reward for information leading to their return.
The band is preparing to kick off their tour Wednesday in Colorado.
The band is known for a string of hit singles, including "American Girl", "Don't Do Me Like That" and "Breakdown."