Mother's horrific confession after killing her three children

Rachel Henry, 22, after being arrested on suspicion of killing her three children. Photo / AP

WARNING: Disturbing content

A woman arrested on suspicion of killing her three young children told investigators that she suffocated her son and two daughters with her hands, police said in court records.

Investigators say Rachel Henry, 22, told them that she thwarted an attempt by her 3-year-old son to protect his 1-year-old sister.

Henry pictured holding a young child in 2013. Photo / Supplied

The boy kicked and punched his mother and yelled for her to stop, but Henry chased him away, according to court records released Tuesday after her first court appearance.

Prosecutors said Henry acknowledged having a history of methamphetamine addiction and that her children had previously been removed from their home by child-welfare authorities in Oklahoma due to issues related to her drug problem.

Henry's family moved to Phoenix in June.

It's unknown whether Henry, who is jailed on a US$3 million bond on suspicion of first-degree murder, has been appointed an attorney who could comment on her behalf.

Investigators say the 1-year-old girl was the first to be killed, followed by her 3-year-old brother, then their 7-month-old sister.

Henry said she sung lullabies to all three children while they were dying.

"Rachel placed all of the children in a position on the living room couch as if they were napping," police wrote.

No motive for the killings has emerged.

Authorities said in court records that Henry wasn't under the influence of drugs or alcohol at the time of the killings.

Henry pictured in jail. Photo / Supplied

Police previously said the two sisters who were killed were 2 and 7 months old. Court records said the older girl was a year old.

During her brief court appearance Tuesday, Henry spoke in hushed tones as she inquired about her bond.

"I don't know how I will be able to get any money," Henry said noting that she doesn't have a job. A relative who lives at the house called police late Monday.

Court records say other people were at the home, but police declined to say whether any of them were there when the children were suffocated.

No one else has been charged.

The Arizona Department of Child Safety didn't have any earlier contacts or abuse reports involving the family, spokesman Darren DaRonco said.