The California Sunday school teacher accused in the shocking kidnap, rape and murder of 8-year-old Sandra Cantu now is being accused of secretly poisoning two people, including another little girl.

The new charges allege Melissa Huckaby, 28, gave "a harmful substance" to a 7-year-old girl in January and an adult man in March, according to the complaint.

The little girl, identified only as Jane M. Doe, has since recovered from the Jan. 17 alleged poisoning. The man, Daniel Plowman, hasn't been located, according to the complaint filed Thursday.

Huckaby's relationship with the two isn't clear, and the type of toxic drug used wasn't disclosed.

Huckaby was in court to enter a plea Friday in San Joaquin County Superior Court to charges that she raped, kidnapped and murdered Sandra Cantu on March 27. But the judge continued the matter until June 12 after public defender Sam Behar asked for time to review the new charges and more than 1,000 of pages of evidence recently provided by the prosecution.

Click here for photos of the Sandra Cantu case.

Sandra disappeared in March after she was last seen skipping away from her mobile home in Tracy, where she lived a few doors down from Huckaby. The girl and Huckaby's daughter were playmates.

Her body was found stuffed in a suitcase retrieved from the bottom of an irrigation pond 10 days after she vanished.

Huckaby, the daughter of a local priest, was charged last month with murder; rape using a foreign object; and lewd or lascivious conduct with a child under 14.

In the new complaint, Huckaby is accused of a single count of child endangerment and two felony counts of furnishing a harmful substance.

According to the complaint, Huckaby "did willfully and unlawfully mingle a harmful substance with food or drink with the intent that (it) be taken by a human being," the Stockton Record reported.

Outside the courtroom Friday, Deputy District Attorney Robert Himmelblau described Plowman as a "victim and a witness" but would not comment further on his connection to Huckaby.

When asked if the new charges related to the Cantu case, Himmelblau said, "You can add counts that don't necessarily relate to the main count if they are same class of crime or are connected."

Himmelblau declined to elaborate, citing the gag order in the case.

During the brief session in a packed courtoom, Huckaby sat calmly in a red jail jump suit and shackles. She did not speak except to answer "yes" when the judge asked whether she understood the case was being further delayed.

Click here for more on this story from KTVU.com.

Click here for photos from Sandra Cantu's memorial service.

The Associated Press contributed to this report.