Yucca Valley resident Matthew Frazer, 42, a former custodian with the Morongo Unified School District, was arrested at his place of employment on January 31.
Frazer is accused of repeatedly sexually abusing a child over a period of several years and sharing depictions of the activity online, according to the U.S. District Attorney's Office.
A federal grand jury in Riverside indicted Frazer on Feb. 12 for production of child pornography. Frazer is alleged to have knowingly enticed a minor to engage in sexually explicit conduct for the purpose of producing pornography.
Evidence indicates Frazer may have victimized additional minors not yet identified.
The FBI began investigating Frazer in 2013 after receiving a series of pornographic images of a 4- to 6-year-old female being abused by a man.
Frazer pleaded not guilty on Wednesday. Frazer's trial is set for April 18. If convicted, Frazer faces a mandatory-minimum sentence of 15 years and a statutory maximum sentence of 30 years in prison.