(CNN) -- Melissa Huckaby, the former Sunday school teacher accused of kidnapping, raping and killing 8-year-old Sandra Cantu, will face additional charges that she tried to poison two people, including another 7-year-old girl.

Melissa Huckaby is charged with killing Sandra Cantu and attempted poisoning of second child.

A revised complaint against Huckaby, 28, of Tracy, California, was made public just hours before she was due back in court on Friday.

The new charges caused another delay in the murder case, CNN afiliate KRON reported.

The complaint charged that Huckaby "did willfully and unlawfully mingle a harmful substance with food or drink" with the intent to harm the child, identified only as "Jane M. Doe."

Another alleged poisoning victim was identified as Daniel Plowman, but no age or other information was immediately provided.

The latest charges also include one count of child abuse endangerment relating to the unidentified child, who was allegedly in Huckaby's "care and custody." Read the complaint (PDF)

Huckaby did not enter a plea in the Cantu slaying in her first two court appearances last month.

At an earlier hearing, Judge Linda L. Loftis agreed to keep the autopsy and toxicology reports under seal, citing a "great danger of public outrage."

If convicted on the murder, rape and kidnapping charges, Huckaby, could face the death penalty or life in prison without parole, authorities said.

CNN's Alan Duke and Jim Roope contributed to this report

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