From your link….
KXAN has asked both Round Rock ISD and the Williamson County Sheriff’s Office why a warrant was issued for the two men instead of a citation. The Williamson County Sheriff’s Office referred us to the RRISD Police Department even though court documents show the sheriff’s office was the arresting agency. A spokesperson for Round Rock ISD did not answer that question but did confirm the Williamson County Sheriff’s Office was the arresting agency.