A man charged with stealing a centuries-old gold bar worth $550,000 from a Florida museum argues that his conviction for murdering his infant son in St. Paul years ago should not be a factor in his bid to be released from jail while awaiting trial.

Richard S. Johnson, 41, and a co-defendant have been indicted by federal authorities in connection with the 2010 theft of the gold antiquity from the Mel Fisher Maritime Heritage Museum in Key West.

The 4⅔-pound breadstick-shaped bar had been secured in a clear case with an opening that allowed millions of visitors to touch it. It was recovered from the Santa Margarita shipwreck by Mel Fisher and his crew in 1980. The Santa Margarita and a second Spanish galleon were among eight vessels that sank in 1622 during a hurricane. The gold bar had been on display for more than 20 years.

Johnson was arrested in late January in the Sacramento area where he was living. He was charged with breaking into the bullet-proof case after the museum closed, while co-defendant Jarred A. Goldman, 32, of Palm Beach Gardens, Fla., stood watch outside. The bar hasn't been recovered.

In 1997, Johnson pleaded guilty to first-degree manslaughter for shaking his 6-month-old son to death when the baby would not stop crying in the family's St. Paul home.

The baby's death came about a month after Johnson allegedly struck the boy's mother during a dispute in Minneapolis. The mother declined to seek charges in that incident.

In March, the museum publicized these surveillance images on Facebook that purport to show Richard S. Johnson during the time of the theft.

Johnson was sentenced to a term of nearly 10 years for killing his son. He served the first 6¼ years in prison and the balance on supervised release.

Other crimes on his record

Last week in federal court in Miami, Johnson's attorney filed a motion to have his client released on bond ahead of trial next month. The defense argued that Johnson is not a flight risk and offered to have him surrender his passport, make weekly check-ins with authorities and wear an ankle monitor while living with his wife at his mother-in-law's home in nearby West Palm Beach.

The defense further argued that the court need not fret about Johnson's manslaughter conviction when weighing whether to grant bond.

"That doesn't have anything to do with theft or anything like that," the filing read. "[It] has nothing to do with whether or not he's a danger to the public or a flight risk."

In arguing to keep Johnson locked up, the prosecution's counter-filing leaned heavily on the manslaughter case, along with his convictions in Minnesota for check forgery, credit card fraud and property damage.

The filing also noted that the bar remains missing and could provide Johnson with great wealth if he fled, that he eluded authorities for nearly eight years, and that a conviction is likely given his misdeed was captured on video.

Johnson's jury trial is scheduled for May 14. In the meantime, his request to post bond and be released awaits a judge's ruling.

One glaring illustration of law enforcement's concern for keeping tabs on Johnson came when he was in court in early March. Museum senior staff were in the court gallery, according to their Facebook posting, when Johnson, weighed down by full leg irons with handcuffs attached to chains around his waist, entered a not guilty plea.

"Oddly the clothing was desert camouflage," the posting read. "Not what we expected."

The Associated Press contributed to this report.
Paul Walsh • 612-673-4482