Sayton Waller, 19, is charged with murder and two counts of attempted murder in the shootings of a young mother and her boyfriend in a car at an Arlington apartment complex on Oct. 7.
The couple's 10-month-old son was in the car at the time, but unhurt.
According to the Jacksonville Sheriff's Office, Waller shot and killed 18-year-old Kamilah Urita and shot Liston Georges III, 20, while they sat in a car with their 10-month-old daughter at the Charter Landing Apartment complex.
Police say Georges remains in the hospital in serious condition.
The baby in the car is the reason for the second attempted murder charge.
Homicide detectives said Georges was the intended victim, as the two had a feud that started when they were in high school.
Police say Waller lived at the same apartment complex as Urita and Georges, and they found physical evidence and a weapon linking Waller to the crime scene.
Police said Herode Joseph, 19, was also arrested in the case, charged as an accessory to murder. Detectives say he is cooperating with police and admitted to witnessing the shooting and driving Waller away from the scene.
Urita's family said she had just moved in to the apartment about two weeks before she was shot and killed.
"He took my friend, my only child, everything from me," said Tamara Jones, Urita's mother. "He didn't even know. She was a good person. He didn't know anything about her, but he took her life and didn't even know her."
Jones said she's glad the suspects were caught.
"I can't wait till I get in court, face-to-face with him and let him know what he did to me," Jones said. "He has really shattered my life."
Urita's 10-month-old son is now in Jones' custody. Jones said she will continue to share those good memories of her daughter with her grandson.