Johnson, left, and Golden entering the courthouse Tuesday

JONESBORO, Arkansas (CNN) -- On his 14th birthday, Mitchell Johnson pleaded guilty to killing four classmates and a teacher and wounding 10 other people. Another Jonesboro boy, 12-year-old Andrew Golden, pleaded not guilty due to mental incompetence but still was found guilty by a judge at a juvenile court hearing Tuesday.

Sentencing was to take place later in the day.

Because they are juveniles, the boys were not put on trial before a jury, were not convicted of murder and were not subject to a life sentence or death penalty. Instead, Craighead County Judge Ralph Wilson Jr. found them guilty of being juvenile delinquents.

The maximum sentence would keep them in a juvenile facility until age 21, but they could be released when they are 18.

Reporter Danny Noa describes the mood of the courtroom: AIFF or WAV (392 K / 31 sec. audio)

In court on Tuesday, Johnson admitted firing shots that cut down teacher Shannon Wright and four of his classmates -- Natalie Brooks, Paige Ann Herring, Stephanie Johnson and Britthney Varner.

A lawyer for Golden said the boy took part in the March 24 attack but was insane at the time and not mentally competent to understand the hearing.

Wilson rejected the argument and found Golden guilty.

Both boys were charged with five counts of capital murder and 10 counts of battery. Nine other students and another teacher also were injured in the ambush at Westside Middle School.

"Ghosts from the Nursery: Tracing the Roots of Violence" by Robin Karr-Morse,Meredith S. Wiley "Before It's Too Late: Why Some Kids Get into Trouble--& What Parents Can Do about It" by Stanton E. Samenow "Theories of Delinquency: An Explanation of Deliquent Behavior" by Donald J. Shoemaker "Safe Passage: Making It through Adolescence in a Risky Society" by Joy G. Dryfoos "Assessing the Youthful Offender: Issues & Techniques" by R. D. Hoge,D. A. Andrews Click here for additional reading on Juvenile Delinquency