Authorities say 28-year-old Efrain Hartley was arrested shortly after the incident, which occurred about 3 p.m. Thursday.
He's being held on suspicion of second-degree murder and aggravated assault.
Glendale police say 20-year-old Shaquille Johnson was fatally wounded while his 24-year-old brother Stephen Johnson remains hospitalized in critical condition.
Police say Hartley dates the brothers' sister. He went to the family home to drive her to work when an argument ensued and shots were fired.
Hartley told police that both brothers came toward him after he told them to stop and he felt threatened.
Hartley doesn't have a lawyer yet for his case.
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