In a videotape played for jurors Tuesday, Maria del Rosio Alfaro told sheriff's investigators that she repeatedly stabbed a 9-year-old girl to death to eliminate her as a witness to a robbery.
Prosecutors said Autumn Wallace was stabbed 50 times in the bathroom of the Anaheim home that she shared with her mother and older sister, neither of whom was at home during the attack on June 15, 1990.
Because the crime allegedly took place during a robbery and burglary, Alfaro, 20, faces the possibility of the death penalty.
Alfaro's attorney, William M. Monroe, has conceded that Alfaro was at the house at the time of the robbery but said a male companion committed the murder.
During the four-hour taped interview, made about two weeks after the killing, Alfaro said she had gotten high and decided to rob the Wallace home and sell the contents to raise money for more drugs.
Alfaro was an acquaintance of April Wallace, 18, the victim's sister, so she knew that Autumn would be home alone in the late afternoon, she said on the tape.
Alfaro said she persuaded Autumn to let her use the bathroom at the back of the house. On the way, Alfaro said, she took a knife from a drawer in the kitchen. After a minute's deliberation, Alfaro asked the girl to come into the bathroom and help her with something.
"That's when I did it. . . . I stabbed her," Alfaro said between sobs on the tape, " 'cause she knew who I was."
The victim, a popular A student at Jonas E. Salk Elementary School, died without making a sound, Alfaro said.
"I was really wired, really coked out," she said. "I got kind of crazy. . . . Something just got into me, and I thought of doing that. I don't know."
But later in the interview, Alfaro said "I wasn't out of my head" when she murdered the girl.
The trial continues today.