The case began as every parent’s nightmare updated for the digital age, for the consumer age, for the time of personalized entertainment and bling. It drew attention as far away as Australia, with the word “iPod” right up there in the headlines.

And it drew closer to an end yesterday, so much as these things end, with one prison sentence and more to come.

Christopher Rose was 15, the sort of boy people would later describe as polite and shy, born to certain small advantages. He was the youngest of four, the only son. He expected a career as an electrician.

Though his family lived in Brooklyn, his father sent him to school in Bushkill, Pa., population 7,880, a 91-mile bus ride northwest, and it was there he was going to visit friends one Saturday afternoon in July 2005, wearing distinctive white earphones with distinctive white wires.

Between the family home in East Flatbush and the subway station, Christopher, who was walking with some friends, encountered a group of teenagers — no one will ever know how many — of the sort often described as troubled. Some had knives. Some would later be identified by the authorities as members of the Crips gang. One was nicknamed Doom.

“Run the iPod,” said one of them, Darran Samuel, 17, using street slang to signal the start of a robbery, according to prosecutors. When Christopher refused, he was stabbed twice in the chest. He died that afternoon.

The robbery was not uncommon, but the object of desire was also one of fascination. IPods, computerized music-players that sell for as much as $400, come equipped with parts that announce their presence on purpose. Their postmodern design has been adopted as fashion by the urban cool.

Just a few months before Christopher was killed, the police announced a sharp increase in subway crime, brought about almost entirely by thefts of iPods and similar devices.

After that, some people began substituting plain headphones for the obvious white ones, but the warnings from the police did little to diminish the popularity of the machines. Last month, Apple Computer, the company that makes the iPod, announced that it had sold 8.1 million of them in three months, a 32 percent increase from the same period in 2005.

After Christopher was killed, Apple’s founder and chief executive, Steven P. Jobs, called the Rose family to offer sympathies. There were calls from around the world and visits from elected officials, said Errol Rose, Christopher’s father.

In State Supreme Court in Brooklyn, four young men were eventually charged with crimes connected to the robbery. Daryl Stephen, 18, is scheduled for trial next month on charges of hindering prosecution. Quaison Fraser, 18, pleaded guilty to gang assault and is scheduled for sentencing today.

Prosecutors have focused their efforts on two cousins. The elder, Aaron Farrell, 20, the one known as Doom, was accused of stabbing Christopher and charged with second-degree murder. Jurors ended deliberations in his case yesterday without a verdict; they were ordered to return today.

The younger cousin, Mr. Samuel, was charged with second-degree murder for instigating the robbery. A prosecutor, Kyle Reeves, said that Mr. Samuel should have known his companions were capable of violence, if only by their gang affiliations and nicknames.

In court yesterday, Justice Alan D. Marrus noted Mr. Samuel’s youth, but spared him little of the maximum penalty of 25 years to life in prison, sentencing him to 22 years to life.

Mr. Samuel rubbed his face. His grandmother wailed. The spectators filed out, parents mostly, and not yet middle-aged. Joanna Samuel, mother of Darran, said her son was a scapegoat.

Mr. Rose, Christopher’s father, spoke of all that time spent riding the bus to Pennsylvania, trying to keep him away from the gamble of the Brooklyn streets.

“For me, forget about it, it’s like half of my life is gone,” Mr. Rose said, “because I took Christopher away from all this.”