Brooks began to feel ill and handed the phone to someone while Jones was on the other end searching her West Baltimore apartment for shoes - any pair would do - so she could rush to the hospital.
"I don't remember who was on the phone then; I just kept saying, `Please tell me my son is not dead, please tell me he's not dead,'" she recalled.
But 20 minutes after being brought unconscious to the hospital where he was born on New Year's Day 14 years earlier, Walker was pronounced dead.
His mother arrived after he died. So did his father, Walker Louis Coleman III - who hadn't seen his son in several weeks.
The next night by a skinny, 6-foot-tall tree at the edge of the playground, where Walker had fallen, dozens of people gathered for a makeshift vigil. At the base of the tree they left lighted candles next to teddy bears, homemade sympathy cards and notes, and empty liquor bottles.
Walker had become a member of a small, tragic group, one of 13 children under age 17 who have been murdered this year in Baltimore.
How did it come to this?
Walker's family and friends had worried his environment could erode his honest hopes. But most said they were stunned that someone could dislike the boy so much that he would be killed.
Not him, they thought. Not the boy who had read books as a hobby during elementary school.
Not the boy who refused to live with his mother because he wanted to care for his sickly grandmother, a role he played so well that his obituary listed him as Brooks' caregiver.
But now all of those people who thought so highly of Walker wonder if they missed or glossed over the warning signs that could have saved his life.
"I can tell you, whatever he got caught up in, it wasn't him; it was the consequences of his surroundings and peer pressure," said the Rev. K.C. Wilks, pastor of First John Tabernacle Baptist Church on East Preston Street in East Baltimore, which Walker had once attended.
"Because the boy had no street knowledge at all," Wilks said. "He was what you call clean-cut. His dress, his mannerisms, everything. A smart kid."
On Sunday mornings at church a few years back, Walker would sit quietly in the back of the room taking in his Sunday school lesson and memorizing Bible verses. While other children might be talking or fidgeting when they should be listening, Walker was always studious.
"He was very, very sharp," said Nathaniel Thomas, Walker's Sunday school teacher at First John Tabernacle. "He was quiet to where if you didn't know him you'd think he wasn't paying attention. But if you called on him, he had the right answer every time."
`Little boy mischief'
At City Springs Elementary School, across Pratt Street from his home, Walker would sometimes cut up in class in the third grade - "little boy mischief," one teacher recalled. But his teachers didn't worry too much.
"He got a lot of attention because he was so smart, and I think his friends started to feel jealous," said third-grade teacher Lauren Brown. "So Walker would act up sometimes just to be like the other boys. But you knew he had potential to be so much more."
By the time he was in fifth grade he was a model pupil, tutoring first-graders in reading and trusted to watch over his class when the teacher stepped out for a brief errand.
His fifth-grade math teacher, Lee Carroll, learned quickly that Walker was a voracious reader. Like some of his other teachers, she tried to nurture his talent. Once, Carroll drove from store to store to find a 500-plus page autobiography by pro wrestler "Mankind" because Walker told her he wanted it.
"He read it and said it was the best book he had ever read," said Carroll, who now lives in California. "He really did have a twinkle in his eye and was so smart and proud of his work."
As his fifth-grade year drew to a close, Walker's teachers implored his family to bypass Lombard Middle School across the street from City Springs and send him somewhere more challenging. They had Roland Park Middle School in North Baltimore in mind.
Walker's family thought Roland Park was too far away, but they liked the idea of a more rigorous academic curriculum and enrolled him in an honors track program at Northeast Middle School.
Walker seemed ready to blossom in middle school. But when he graduated from City Springs - dressed neatly in a dark suit and tie, proud of the math achievement award he had won - he lost a lot.
He no longer had teachers who would look past his disobedient moments. At Northeast, Walker was just another kid in a school of 850.
Without the extra attention, he began to struggle.
His stubbornness irked teachers, who eventually labeled Walker a problem pupil. In the seventh grade, his poor behavior got him kicked out of the honors program.
In the eighth grade, he was suspended for threatening to slap a teacher, and several other times he was kicked out of class for minor offenses: not removing his earphones, or not opening a textbook when told.