A fiery Clayton County Superior Court Judge Deborah Benefield pointed out a key shortcoming of Bun's as she gave out the sentence.
"In the presence of this court, he has never shown any remorse," Benefield said.
As Bun approached the judge with his attorney Lloyd Matthews, he spoke.
"I want to apologize to Daly's family," Bun said.
Bun was 17 on July 20, 2011 when he shot and killed Daly.
A recent decision by the U.S. Supreme Court prohibited mandatory life-without-parole sentencing for murder convicts younger than 18.
Earlier in the hearing Thursday, Benefield struck down a constitutional challenge to the life-without-parole sentence for Bun that was based upon that Supreme Court ruling.
"This court does not find the sentencing statutes to be unconstitutional as applied in this case or otherwise," Benefield said. "That was clearly said by the majority even in the recent decision ... [while] it was unconstitutional for [life without parole] to be mandatory, it was important for there to be judicial discretion.
"Georgia statute allows for judicial discretion."
The judge made that first decision after hearing defense witness Emory University professor and child psychiatrist Dr. Peter Ash testify on the level of culpability juveniles might have for criminal behavior.
"Juveniles are impulsive and immature, and pay more attention to immediate reward," Ash said. "Under stress, their decision-making skills are not as good as adults."
In questioning the fairness of condemning a teenage offender to life in prison, Ash suggested that at such a young age Bun still had a capacity to change.
"We cannot predict how juveniles ... even a severe offender, might behave as an adult," he said.
But Lawson, who spent 13 years with the Clayton juvenile justice system before becoming the county's head prosecutor in 2008, outlined a pattern of criminal behavior dating back to when Bun was 10 years old.
"I probably saw over 17,000 juveniles," she said. "This one was unusual. From the time he was 10, his family was afraid of him."
And after Bun remained in the juvenile justice system without improving -- even spending seven months receiving therapy and treatment at Macon Behavioral Health Center -- she requested that he remain in juvenile custody.
According to court testimony, at age 10, Bun brought a knife to school. By age 16, he'd been arrested for burglary, drugs and trespassing and was a known member of the Bloods gang when he was accused of robbing a store at gunpoint in January 2011.
"He escalated in his behavior from age 10 through now 17, culminating in one of the worst offenses that one human being can commit against another," Lawson said. "When I'm telling you, we tried everything in the universe to change this young man, he can't be changed."
Less than a month before the shooting, prosecutors said Bun pulled another armed robbery at a beauty salon, taking between $600 and $800 in cash from the business and the half-dozen workers and customers there with the help of Xavier Carter.
Carter testified against Bun in exchange for a reduction of his armed robbery charge.
On the afternoon of July 20, Daly pulled Bun and a friend over to serve an arrest warrant on the teen, who was wanted in a January 2011 armed robbery.
Witnesses testified that Bun stepped from the passenger side of the car he was riding in and opened fire on Daly, who was in uniform.
Daly died at the scene, and Bun fled to a nearby wooded area, prompting a massive manhunt that involved more than a dozen area police agencies.
Thursday, Daly's daughter beseeched the court to apply the stiffest penalty to the teen.
"It's changed our lives forever," Amber Wright said from the witness stand, as she looked through tears at Bun. "He doesn't deserve to walk free."
Daly's wife of 37 years, Cheryl Daly, followed her daughter with her own demand that Bun see no mercy.
"I believe he should get life without parole because he took my husband's life," Cheryl Daly said. "He should pay with his own."
Lawson said as a juvenile judge that she feared for the community if Bun were released.
"We had a saying ... don't lock them up when you're mad at them, lock them up when you're afraid of them," Lawson said. "I was afraid he was going to harm the community."
In handing down a life sentence for killing a lawman and adding seven decades of prison time for additional charges ranging from aggravated assault to theft by taking, Benefield sent a message.
"Make no mistake, there are great forces of good and evil in this world," Benefield said as she visibly fought back emotion. "When an officer dies so that others are protected, good prevails.
"This is not the time to wring our hands and wish it weren't so. It is time to stand and say, 'Not on my watch.' Rick Daly's light shines on."