He was arraigned in Kanawha County Magistrate Court and ordered held in the South Central Regional Jail in lieu of a $30,000 cash-only bail.
White said Elswick appeared to be "possibly under the influence of an unknown substance."
Deputies don't know why Elswick would have been on school property and don't have a motive for his actions.
Evans and Cpl. A.J. Miller received medical treatment after the incident. Miller sustained a fracture to his hand during the altercation with the suspect.
Robbins said there was no danger to students. School continued as normal.
Staff Writer Travis Crum contributed to this report.
Reach Kathryn Gregory at kathr...@wvgazette.com or 304-348-5119.