The suspect is being held at the Kings County jail. Authorities say she is pregnant with her fourth child. Investigators believe she killed the little girl over potty training.
Jacqueline Arellano is overcome with grief. After saying goodbye to her 2-year-old little girl Yeily Guadalupe -- the baby was taken off life support Monday and died shortly after.
Arellano is suffering from terminal brain cancer and undergoing chemotherapy so she was unable to care for her child and gave legal guardianship to her uncle and his wife, Rosa Ramirez-Najar.
Kings County investigators were called to Ramriez-Najar's house on Kansas Avenue south of Hanford on Friday, where they say Yeily had been beaten so severely, she was left brain dead.
Sgt. Pete Thompson with the Kings County Sheriff's Office said, "We do know that the suspect was frustrated with the child's lack of potty training and trying to train the child and during that the child was injured."
They say the toddler had numerous fractures to her skull and wrist. They also found injuries that show a history of abuse. Investigators say Ramirez-Najar has three children, and is currently pregnant with her fourth.
Sgt. Thompson added, "Biological children to the suspect are with CPS and in foster care so neither the father or the mother have custody of the kids obviously the mother's in custody."
While Arellano mourns the loss of her daughter, she's looking to friends to help comfort her, and remember her daughter.
Family Friend April Zamaripa said, "I don't know what to say to comfort Jackie in this situation because she's fighting with her own cancer right now and it's crazy that for someone to go and take someone's life I don't understand who this lady thought she was."
Arellano told ABC30, "She loved Mickey Mouse, she would want kisses from mommy and she would stretch out her lips for a kiss."
Ramirez-Najar is in custody on a felony charge of child abuse causing brain damage. But now that the little girl has died. Investigators say they'll conduct an autopsy Tuesday and will likely file murder charges after the results come in.