The man who stabbed a 17-year-old to death at a Chula Vista house party in 2022 has been sentenced to 12 years in prison. James Mumper Jr., 19, was sentenced in Chula Vista court on Friday for voluntary manslaughter, use of a deadly weapon and other charges related to the fatal stabbing of 17-year-old Mateo Alexander Castillo in November 2022. “We all grieve with the family for the loss of such a young life taken by senseless violence,” San Diego District Attorney Stephan said. “We hope the family can find solace in the justice that was delivered through this prosecution.” MORE: https://www.cbs8.com/article/news/local/man-sentenced-to-12-years-for-fatal-chula-vista-house-party-stabbing/509-77a8bb60-0f36-4c89-91d3-284538984ffb