Pasco County sheriff's detectives arrested Kimberly Smith Friday on drug possession charges, WTSP-TV, St. Petersburg, reported.
Smith was confronted by school officials earlier in the week and resigned.
Pasco Schools spokeswoman Linda Cobbe said the situation was uncovered when parents of a student at New River Elementary came to the school to tell administrators they didn't want their child to be taking Ritalin, which is prescribed for children diagnosed with attention deficit disorders. When the bottle of pills was returned, "they realized there were pills missing," Cobbe said.
The state suspended Smith's license, WTSP said. The arrest report alleges Smith "personally" used the stolen pills and tried to cover up her actions by coloring white pills with a yellow highlighter.
"One of the pills should have been all yellow and there was another pill that was found in there that looked like it had been altered, maybe with a highlighter of some sort," Sgt. Chris Beaman, a member of the Pasco sheriff's narcotics unit, told WTSP.
Cobbe said school officials couldn't recall a similar incident.
"We are just sickened that she would do this," Cobbe said.