However, jurors didn't find that Burton was the person who shot Boyer, who lived in Dublin and had been married for less than a year.
Boyer crashed his car down a ravine in the 5200 block of Keller Avenue after he was shot and died two days later of a single gunshot wound to his head.
Boyer grew up in Oakland and had been in the city that day to take his father to a medical appointment.
Alameda County prosecutor Jimmie Wilson said after the verdict that he believes Burton was the shooter but jurors had reasonable doubt about that because the only eyewitness in the case, a woman who's now 80 years old, identified another teen, Nazhee Flowers, as the person she thought shot Boyer.
Alameda County Superior Court Judge Kevin Murphy said at the sentencing hearing March 22 that the "ambiguity" about whether Burton, who was with five other teens at the time, was the shooter is one of the reasons he decided to sentence Burton to 25 years to life instead of life in prison without parole.
Murphy said another reason is that Burton didn't have a significant previous criminal record.
Burton's lawyer Ernie Castillo said sentencing Burton to life in prison "would be too oppressive, too excessive" because he has a very low IQ, suffers from a learning disability and grew up in a troubled and abusive home.
But Wilson asked for the maximum sentence possible, saying, "I don't think Mr. Burton cares about what he did. I think that's sad and that's tragic."
Boyer's wife Liz Boyer also said that during the six years of Burton's legal proceedings, "I've seen nothing to show that Mr. Burton really cares about the level of devastation he's caused, the amount of pain."
Liz Boyer said she and Quinn Boyer had been married for less that a year when he was killed and the day before the shooting he had surprised her by buying plane tickets to Hawaii to celebrate their first anniversary.
Wilson said during Burton's trial that the fatal shooting of Quinn Boyer occurred during a crime spree in which he and the five other teens who played hooky from school on that spring day committed two carjackings and a robbery in addition to the shooting.
Wilson alleged that the teens wanted to carjack Boyer's Honda Civic, as he had pulled his car off to the side of the road to use his cellphone.
But Castillo told jurors in his closing argument that they should find Burton not guilty because the eyewitness's description of the shooter matched Flowers, not Burton.
This was Burton's second trial for the death of Boyer because his first trial in 2015 ended in a mistrial with jurors deadlocked 7-5 in favor of finding him guilty.
Co-defendant David McNeal, who was 15 at the time of the shooting, was found guilty of first-degree murder in that same 2015 trial and was sentenced to 48 years to life in state prison for his role in the crime, which was providing the gun that was used to kill Boyer.
Three of other teens involved in the crime pleaded guilty to first-degree murder in juvenile court for being accessories and are serving their sentences with the state Division of Juvenile Justice.
Flowers, the person who Castillo alleges was the teen who shot Boyer, pleaded guilty in adult court to a carjacking charge and was sentenced to 15 years in state prison.
This story contains 637 words.
Stories older than 90 days are available only to subscribing members. Please help sustain quality local journalism by becoming a subscribing member today.
If you are already a subscriber, please log in so you can continue to enjoy unlimited access to stories and archives. Subscriptions start at $5 per month and may be cancelled at any time.