Both Justin Guzman and Marko Cinan are accused of shooting Anthony Sanders multiple times inside the Galleria's orange parking garage on June 3.
During Guzman's court appearance, officials said Sanders' fiancee encountered three men in an elevator in the Galleria and one of them insulted her.
She told Sanders, who was picking her up from work, and he tracked the men down and exchanged words, according to court officials.
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Cinan, who is friends with Guzman, is accused of brake checking Sanders, and he and Guzman are accused of firing multiple shots even as they drove away.
Only ABC13 cameras were present as Guzman turned himself in at the Harris County Joint Processing Center on Monday afternoon.
Just before 4 p.m. on Monday, Guzman got out of an Uber, accompanied by his attorney, Romy Kaplan, to face murder charges.
Kaplan says Guzman was defending himself because Sanders allegedly walked toward him with a knife in the parking garage.
Initial court records showed that Sanders was unarmed, but Kaplan says he's confident that he could sort out the specifics during the legal process.
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Eyewitness News learned during Tuesday's court hearing that a gun was found where Guzman was sitting in the car, and it "contained 10 unfired rounds out of a 17-plus one capacity."
Cinan was charged last week with Sanders' murder. He remains in jail on a $1 million bond.
At Cinan's court hearing on Monday, Sanders' parents spoke out. Ronyel Sanders said that the two sides got in an argument, but that Sanders was just trying to leave.
Guzman was charged on Monday, and a judge set Guzman's bond at $750,000 on Tuesday. He is due back in court on Wednesday.
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Only on 13: 2nd suspect charged with murder in connection to deadly Galleria parking lot shooting