MARTINEZ -- At the sentencing for her son's killer Friday, Karen Williams-Harmon showed off the senior portrait that 17-year-old Rylan Fuchs took for a high school graduation that he did not live to see.

"Why? Why? For pot? For territory? Was all this worth the life of my son?" Williams-Harmon asked 22-year-old Walter Bell, convicted of special circumstance murder for fatally shooting Fuchs outside his family's Danville home during a marijuana robbery on Jan. 20, 2009.

Bell, of Berkeley, did not make a statement at the hearing where he was sentenced to a mandatory term of life in prison without the possibility of parole.

He was only 18 when he was part of a crew of young men who went to Rylan's house under the guise of buying a few ounces of marijuana from the popular San Ramon Valley High School senior. Set up to be robbed by a former classmate associated with Bell, Rylan sneaked out a window after a family dinner to meet the would-be buyers and was shot in the neck when the robbery went wrong.

His mother's then-fiance, now husband, Ron Harmon, said he heard a "pop" and then a "thud" at the front door. He opened the door, and a wounded Rylan fell into his arms.

"I know it sounds crazy," Harmon said Friday, but he was too confused at first to recognize Rylan.

"I had just talked to him and I was sitting by the front door, and I didn't see him exit the door," Harmon recalled in court.

Harmon used his military training to try to save Rylan as Rylan's 9-year-old brother, Trey, rushed to bring towels.

Before dawn the next morning in a hospital room, Trey said goodbye to his big brother. Though Rylan was only a shell of himself, his mother said, a tear ran down his face.

That sometimes happens, a doctor told Williams-Harmon. She believes it was Rylan's way of saying goodbye.

"Four years ago is like yesterday to us," Williams-Harmon said. Turning to Bell, she asked, "Do you know you took away the biggest smile the world has ever seen?"

Bell's own relatives sobbed in the courtroom Friday; his father was eager to be heard. He thought the punishment was too severe and asked the judge for mercy that she was legally unable to provide because Bell was convicted of first-degree murder charges that would have made him eligible for the death penalty had the Contra Costa District Attorney's Office opted to pursue capital punishment.

Bell's defense at trial was that he was not the shooter, but witnesses testified that, before his arrest, he told several people that he killed Rylan.

"I'm very sorry you lost your son in the horrific way that he died," Walter Bell Sr. told Rylan's family. He said his son is "not a coldhearted murderer," and he's loved by his family.

"I'm losing a son here today," Bell Sr. said. "It's hard for me. This is a very emotional time, I'm just trying to speak for my son like they spoke for theirs.

"I love my son."

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.