A California man was convicted Tuesday in two high-dollar heists at jewelry stores in Charleston and Columbia.

A jury found Charles Eloys Johnson, 35, of San Leandro guilty of five federal charges at the end of a four-day trial in U.S. District Court in Charleston. Judge Richard Gergel did not immediately sentence Johnson.

Federal prosecutors who announced the conviction said Johnson was part of an Atlanta-based group that robbed Sylvan Jewelers in Columbia in February 2015, then Demetre Jewelers on Charleston’s King Street two weeks later.

The Charleston store’s owner reported on March 4, 2015, that two masked men broke a display case with a hammer and stole about 60 Rolex watches. One of them had a gun. The loot was valued at $700,000.

Johnson was the first of three suspects to be tried in the robberies. Aquabeus Moore, 34, of Riverdale, Ga., and Jerry Harbin, 29, of Antioch, Calif., also were indicted on federal charges.

Johnson’s convictions came on one count of conspiracy to commit robbery affecting interstate commerce and two counts of robbery — each of which carry up to 20 years in prison. The jury also found him guilty of two counts of brandishing a firearm in a violent crime. Together, the gun convictions carry a mandatory 32 years in prison in addition to his sentence on the other charges, according to the U.S. Attorney’s Office. He could serve up to life behind bars, the prosecutors said.

A sentencing hearing was not immediately scheduled.

Assistant U.S. Attorney Nathan Williams and Acting U.S. Attorney Beth Drake prosecuted the case. The FBI and police departments from Charleston and Columbia investigated it.

Reach Andrew Knapp at 843-937-5414 or twitter.com/offlede.