But Teresa Robles insists she's telling the truth now by blaming the crime on her boyfriend, Jose Velarde.
The couple is accused of killing the victim and burning her body in 2010.
The district attorney asked Teresa Robles "can you keep track of all the lies you've told?" and she answered "no." She also answered "I don't know" to a lot of questions, and at one point during her testimony a juror even blurted out a comment.
Prosecutors went on the offensive Tuesday, accusing Teresa Robles of making up lie after lie to avoid taking the blame for the murder of Ana Diaz de Ceja and the kidnapping of her baby boy.
Teresa told jurors on the day of the crime, she sat on the floor of the master bathroom in her Planada home with the fan on so her boyfriend, Jose Velarde, could speak privately with Ana.
She said she had no idea he was strangling the young mother just a few feet away in the bedroom until she walked out and saw a horrific scene: Ana's lifeless eyes and Jose's hands still around her neck.
The district attorney asked how it's possible she didn't hear Ana screaming or fighting, and Teresa replied she had her hands over her ears - something she's never said publicly before. In fact, she told detectives she was holding the infant during the attack and that it took five minutes for Ana to die.
"Little by little her holes are getting poked at, and everything is going to come out," Yanira Grandados, the victim's cousin said.
Teresa also testified Jose told her he had an affair with Ana and that Anthony was his son. The district attorney asked if Jose already had a little boy on the way, why did Teresa go to a Merced park weeks earlier and offer a man 15 hundred dollars to kidnap a baby and hurt the mother. She replied "I don't know."
"She doesn't know because she's lying. So she can't keep up with her lies," Grandados said.
Teresa admits she lied many times during the investigation, but says it's because she feared and loved Jose. She also claims he got her hooked on methamphetamine before the crime, so she wasn't thinking clearly.
Teresa testified Jose pressured her to pretend she was pregnant then carried out the crime and burned Ana's body in this orchard near Snellling. She also blames him for leaving two month old Anthony on a doorstep in Le Grand five days later. The victim's family members say the more than month long trial has been grueling.
"We're just anxious for it to just be over and for them to sent away forever," Grandados said.
Jose Velarde did not testify in his own defense, but he could be called as a rebuttal witness after Teresa's testimony.
Attorneys say they hope to present closing arguments to the two different juries hearing this trial by next week.