Umeir Corniche Hawkins shot 50-year-old Jerry Lewis on July 5, the Los Angeles County District Attorney's Office said.
Prosecutors say the two men began arguing when Lewis entered the market without wearing a face mask. Lewis then left the market but when he returned the two fought again and Hawkins fatally shot him as he walked away, prosecutors said.
Hawkins is now charged with murder and possession of a handgun by a felon. His wife, Sabrina Carter, also is charged with one count of possession of a handgun by a felon. The couple was convicted in 2013 for assault by means of force likely to produce great bodily injury. Attorneys for Hawkins and Carter did not immediately respond to CNN requests for comment
The two pleaded not guilty to the charges Wednesday. Hawkins is being held on $1 million bail and faces 50 years to life in prison if convicted. Carter's bail was set at $35,000. She faces up to three years in prison.
They are scheduled to return to court on July 10.