Detectives fear there may be more victims.
Authorities arrested 28-year-old Maci Rodriguez on Tuesday.
The sheriff's office says she was an after-school tutor at Kerman Floyd Elementary and also worked for "Teaching Fellow," which contracts with Kerman Unified.
Investigators say Rodriguez was exchanging sexual messages with a middle school student who previously attended Kerman Floyd Elementary, but there's no evidence of a physical relationship.
Rodriguez is booked into the Fresno County Jail on charges including arranging to meet a minor for sexual purposes.