NEW YORK — A teenager who was part of a gang that stabbed a 15-year-old boy to death during a fight over an iPod was convicted Tuesday of robbery and second degree murder.

Brooklyn District Attorney Charles Hynes said a jury deliberated for only three hours before convicting Darren Samuel, 17, of participating in the mugging and fatal stabbing last July.

Samuel, who was 16 at the time of the attack, could get up to 25 years in prison when he is sentenced next month.

The victim, Christopher Rose, was stabbed in the chest when he and friends resisted a group of toughs who accosted them in the street and demanded they give up an iPod one of them was carrying.

During his trial, Samuel admitted being with the group that robbed Rose, but said he “froze” when the mugging began and did not participate in the attack.

He blamed the stabbing on his 20-year-old cousin, Aaron Farrell, who is scheduled to be tried on murder charges next month.

An additional 18-year-old defendant is awaiting trial on a charge of hindering prosecution. A fourth person involved in the attack, Quaison Fraser, 18, pleaded guilty to a charge of gang assault and is expected to be sentenced to 3 1/2 years in prison.

The attack was part of a wave of robberies fueled by the popularity of the iPod, which are easy to grab, can be worth hundreds of dollars, and often contain hundreds, or even thousands of dollars worth of music.

New York City police reported a surge in juvenile robbery arrests in 2005, in part due to kids robbing other kids of the players. Snatchings of the pocket-sized devices also became common on the city’s subways.

Rose split his time between New York and East Stroudsburg, Pa., where he lived during the school year with his father. His family said they felt he would be safer going to school outside the city.