( CNN ) -- A 10-year-old Southern California boy is in a juvenile detention center after denying in court Thursday a charge that he murdered another child , authorities said . The mother of the alleged victim , Ryan Carter , said on HLN 's `` Nancy Grace '' show that the suspect was her 12-year-old son 's `` best friend . '' Lisa Carter , a registered nurse , said that her son died after stepping in front of the 10-year-old as he was trying to stab another child . `` The things we taught him cost him his life , '' Carter said of her son . `` We taught him do n't start a fight , do n't run away from a fight ( and ) if you see a fight ... stop it . '' The San Diego County Sheriff 's Department received a call shortly after 1 p.m. Monday about the stabbing in Lakeside , which is about 20 miles northeast of San Diego . Despite efforts by sheriff 's deputies , paramedics and hospital staff to save him , the boy was pronounced dead around 2:30 p.m. Monday , the sheriff 's department said in a statement . The San Diego County District Attorney 's Office filed murder and felony charges Wednesday against the 10-year-old suspect , said Steve Walker , a spokesman for that office . An attorney for the young suspect `` denied the charges '' during his arraignment Thursday morning , according to Walker . The boy -- whose name has not been made public , in accordance with the district attorney 's policies regarding juvenile suspects -- is now being held in a juvenile detention center in the county , he added . Lisa Carter said that the boy who stabbed her son was actually targeting another child . `` Ryan took the knife for that boy , '' she said , describing her son as intelligent , caring and `` everything to me . '' The victim 's father , Glen Carter , called his son a `` good ... boy with Christian values . '' Since he is a juvenile , the boy accused of killing Ryan Carter can not be found guilty but can be convicted on a `` true finding of fact , '' explained Walker . In convicted , he would have to be released by the time he turns 25 years old , if not earlier , the district attorney 's spokesman added . The boy 's next court date -- for a `` readiness '' hearing to determine if all sides are prepared to move forward -- is scheduled for February 23 . HLN 's Emily Barsh and CNN 's Greg Botelho and John Fricke contributed to this report .
A boy , 10 , is arraigned in a federal court on charges of battery and felony assault . He is being held in a juvenile detention center , a district attorney spokesman said . The mother of the youngest victim , 12 , says her son died trying to break up a fight . She describes her son as intelligent and caring , adding he was ` ` everything to me ''