MONTEREY PARK — It was more than nine years ago that 15-year-old Schurr High School sophomore Brenda Sierra left for school and never returned. 

Still, detectives continue turning up new information in the case and family members have not given up on finding justice for the slain girl and her killers.

Sierra, an East Los Angeles resident, left for a friend’s house on her way to Schurr High School in Montebello on the morning of Oct. 18, 2002, Lt. Dave Coleman of the Sheriff’s Homicide Bureau said. She was kidnapped from the corner of Whittier Boulevard and Leonard Avenue in East Los Angeles.

The next day, her body was found beaten to death in the Valley of Enchantment area of Crestline in San Bernardino County. Police believe her murder was a message to the community from gangs not to cooperate with police…