On Tuesday night, Tracy Police were also reaching out for more evidence.
"What we're asking is for the public that if they have any indication that any of their children had inappropriate contact with Miss Huckaby to contact us," said Tracy Police Sgt. Tony Sheneman.
Sandra played with Huckaby's 5-year-old daughter. Police say she was also questioned.
"The daughter who was there supposedly at the time of the abduction, has she given you any information that may have led to the arrest?"asked ABC7's Alan Wang.
"That's a good question, one that I can't answer," said Sgt. Sheneman.
Tracy Police said the autopsy has been completed, but the cause of Sandra's death may not be released until the toxicology results are back.
Around 1 p.m. on Tuesday afternoon, Melissa Huckaby was led into a San Joaquin County courtroom in a red jumpsuit and shackles for the afternoon arraignment.
She cried as a judge read the charge: one count of murder with the special circumstances of rape with a foreign object, lewd or lascivious conduct with a child under 14 and murder in the course of a kidnapping.
She did not enter a plea.
The little girl's body was discovered last week in a Tracy irrigation pond. She was stuffed in a suitcase that Huckaby had told police was stolen from her.
Melissa Huckaby lived just five doors down from the Cantu family, and her 5-year-old daughter often played with Sandra.
The hearing lasted approximately four minutes and there were about 100 people in the courtroom. Family members from both sides were in there as well. There were tears on both sides and from the defendant.
"On or about March 27, 2009 the crime of murder in section 187 of the penal code of felony was committed by Melissa Huckaby," read Superior Court Judge Richard Vlaviano.
Murder defendant Melissa Huckaby began to sob as the judge read the charge against her in a Stockton courtroom, including the special circumstances.
"While said defendant was engaged in the commission, attempted commission, or attempted commission the crime of rape by instrument..." read Superior Court Judge Vlaviano.
Huckaby, a single mother and Sunday school teacher, is now eligible for the death penalty if the district attorney decides to pursue it once the case goes to trial.
"Consistent with our policy with regard to the handling of all special circumstance murders, we will not make a decision about whether to seek death until we're further down the road in these proceedings," said James Willett, the San Joaquin County District Attorney.
Outside court, Huckaby's father Brian Lawless told ABC7 the allegations against her don't fit the daughter he knows.
Sandra Cantu's father, Daniel Cantu, said nothing to reporters as he left wearing a t-shirt with his daughter's picture on it. Sandra's aunt, uncle and other family members also left the courthouse without talking to reporters.
Among the spectators in the courtroom were several people who say they knew Sandra, the little girl with the bright smile who met her fate so close to home.
"Once I heard it was the lady that actually lived in the same place, in the same area, it just made me break down really bad," said Ericka Orozco from Tracy.
"I just probably would've asked her 'Why? Why did you do that to her? What was going through your mind? If you needed help why didn't you seek it?'" said Josie Orozco from Tracy.
Investigators are clearly not finished building their case against Huckaby. Within hours of her court appearance, Tracy evidence team executed two more search warrants. One at her home, and one at the church where she taught Sunday school.
Huckaby will be represented by a public defender. Someone in that office told ABC7 they will seek a gag order in this case, but they do not plan to seek a change of venue.
Legal experts say that of all the types of people law enforcement investigators could have suspected, Melissa Huckaby did not fit any such profile.
Public Service for Sandra Cantu:
Thursday, April 16, 2009
1 p.m. - People are asked to arrive early since there will be limited parking
Merrill F. West High School
1775 West Lowell Avenue