Updated

PHOENIX -- A 15-year-old Liberian refugee who pleaded guilty to participating in the gang rape of an 8-year-old girl was sentenced to probation.

Maricopa County Juvenile Court Judge Samuel Thumma Wednesday also sent the boy to a secure treatment center for at least a year for last summer's assault in Phoenix.

The Associated Press is not naming the teen because of his age, 14 at the time of the assault and the oldest of four boys accused.

He was originally charged as an adult but later sent to juvenile court where he pleaded guilty to sexual assault, kidnapping, three counts of sexual conduct with a minor and one count of attempted sexual conduct with a minor.

Unless a judge rules otherwise, he will remain on probation until he is 18. If he had been convicted in adult court, he could have been sentences up to 21 years in prison.

Prosecutors said the girl was lured July 16 to an empty storage shed at a west Phoenix apartment complex with the promise of chewing gum. The oldest boy admitted holding the victim down while he and three other boys -- ages 9, 10 and 13 -- sexually assaulted the girl, according to authorities.

"I struggle to figure out how anything like this could have happened," said Thumma.

The teen apologized at the hearing.

The two youngest boys have been found incompetent to stand trial, while the other boy's case is pending.

All of the children, including the victim, are Liberian refugees.

The girl is in foster care. Her parents were charged with child abuse but were released from jail last month because the court was unable to provide interpreters for court appearances.

The case prompted an international outcry after police reported the girl's father said she brought shame on the family and he didn't want her back -- comments a family pastor later said were misunderstood because of a language barrier.