PHOENIX (AP) — 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. 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 $3 million bond on suspicion of first-degree murder, has been appointed an attorney who could comment on her behalf.

Investigators said 1-year-old Miraya Henry was the first to be killed, followed by her 3-year-old brother Zane Henry, then their 7-month-old sister Catalaya Rios.

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

No motive has emerged. Authorities said in court records that Henry wasn’t under the influence of drugs or alcohol at the time of the killings.

Court records said the older girl would have turned 2 next week.