The Supreme Court on Monday agreed to decide whether juveniles convicted of killing someone may be locked up for life with no chance of parole, a follow-up to last year's ruling barring such sentences for teenagers whose crimes do not include killing.

The justices will examine a pair of cases from the South involving young killers who are serving life sentences for crimes they committed when they were 14.

Both cases were brought by the Equal Justice Initiative in Montgomery, Ala. The institute said that life without parole for children so young "is cruel and unusual" and violates the Constitution.

The group says roughly six dozen people in 18 states are under life sentences and ineligible for parole for crimes they committed at 13 or 14.

Kuntrell Jackson was sentenced to life in prison in Arkansas after the shooting death of a store clerk during an attempted robbery in 1999. Another boy shot the clerk, but because Jackson was present he was convicted of capital murder and aggravated robbery.

Evan Miller was convicted of capital murder during the course of arson. A neighbor, while doing drugs and drinking with Miller and a 16-year-old boy, attacked Miller. Intoxicated, Miller and his friend beat the man and set fire to his home, killing the 52-year-old man. Miller's friend testified against him, and got life in prison with the possibility of parole.