According to the Louisiana Department of Education you'll need to contact your local school board to obtain a duplicate diploma. In your case since Capitol High school was a part of East Baton Rouge School District until recently you may want to contact both the EBR School Board and the Recovery School District. You can however just request your transcript via the Louisiana Department of Education's Duplicate Transcripts Office, which lists the transcript request form here. They require a payment of $5.00.
