Melissa Huckaby is charged with kidnapping, raping and killing Cantu late last month. Cantu was a playmate of Huckaby's young daughter.
And now, the mother of a 7-year-old girl tells reporter David Begnaud of CBS station KOVR in Sacramento, Calif., that Huckaby took the girl without permission to a nearby park in January, and may have drugged her.
All three families live in the same mobile home park in the Northern California town of Tracy.
The woman, identified only as Lora, asserts that police didn't do enough to investigate Huckaby after the January incident.
"I believe," Lora told Begnaud, "if Tracy police had looked into Melissa a lot more than they did, I believe Sandra might be alive. ... I kept telling them to look into Melissa Huckaby a little bit more."
Lora says Huckaby took her daughter to the park without permission and, when she came home, her daughter could barely walk.
Lora says her daughter didn't say Huckaby had given her any pills. The girl told Lora, "The only thing (Huckaby) got her was a water from Wendy's."
Lora now questions why authorities didn't take her claims against Huckaby seriously. "I'm just kind of disappointed in them that they didn't look into Melissa more than they did," Lora remarked to Begnaud.
Tracy Police Sgt. Tony Sheneman says there was "no probable cause to arrest anyone" at the time.
Lora says she wasn't surprised when Huckaby was arrested. "My gut feeling," she tells Begnaud, "tells me she did it."
And Lora believes her own daughter is lucky to be alive, saying, "I'm thankful she is OK, and my heart goes out to Sandra's family."