INDIAN WELLS, Calif. -

A photo of a topless little girl, downloaded four times, is among what was found on 59-year-old Robert Keith Bryan's computer at work, authorities said.

The Gerald Ford Elementary School teacher faces charges of lewd acts on a child under 14 years old, and annoying or molesting children, following an investigation that started back in July and led to his arrest last week.

"At this point, the investigation is still open. We've been contacted by numerous people in the community. We're investigating all additional leads at this time and any possible incidents with the suspect," said Capt. Kevin Vest of the Riverside County Sheriff's Office.

Investigators discovered more alleged victims.

Search warrants indicate more than half of the girls in Bryan's 2011-2012 fourth-grade class claim he touched them in ways that made them feel "uncomfortable" or "weird."

Bryan was under investigation in 1992 and 1994 after several incidents at different schools.
He was warned by the Desert Sands Unified School District to avoid touching and being alone with his students.

Stored on the computer and in his classroom drawer at the school, investigators also found several photos of young girls in provocative poses.

The desktop had several thousand pictures of students and for every one picture of a boy there were approximately 15 images of girls, authorities said.

"We just need to sift through everything we have so far, contact potential victims and additional witnesses," said Lt. Lori Marquette of the Riverside County Sheriff's Office.

Bryan's attorney says the fourth-grade teacher "vehemently denies" the allegations.

Jeff Kaye, the director of security for DSUSD, said the district is cooperating fully with the investigation.

Kaye said the district has security firewalls installed in all of their campus computers, which block profanity and trigger an alert whenever someone is working an inappropriate search.

However, investigators said there are many ways around the firewalls to download and upload provocative images.