The hearing was delayed on Wednesday after the court learned that lawyer James Gass, who represents Gallion, was in court on another case.
At a preliminary hearing, judges listen to witness testimony - often from law-enforcement officers - and review evidence to determine if sufficient probable cause exists to hold defendants for trial.
Laurie Cone reported her estranged husband's death to police on April 2 when she returned to his home and reported finding his body about 4:20 a.m.
She and her daughter, Jackie Cone, had spent the evening gambling at San Manuel Indian Bingo and Casino. About 20 guns and John Cone's Ford F-150 pickup were missing.
Police say an investigation showed that Laurie Cone conspired to have her husband killed for personal financial gain.
John Cone operated a television- repair shop, D/C Radio and Television, out of the home in the 2100 block of Sierra Way.
Laurie Cone, 47, Gallion, 29, and Bayless, 39, all of San Bernardino, are each charged with one count of first-degree murder in connection with the death of John Cone, 64.
Gallion and Bayless also face one count of first-degree residential robbery and one count of first-degree burglary.