Children Photo courtesy Maricopa County Jail.

On Tuesday, Phoenix Police released a report detailing how a Phoenix mom smothered her three children – a gruesome account that is now making national headlines.

On Monday, Rachel Henry admitted to killing her 3-year-old son, 1-year-old daughter, and 7-month-old daughter, according to the report. Henry is accused of smothering them to death, singing as she did so.

“Rachel described singing to the three-year-old male, while she placed her hand over his nose/mouth,” the report said.

After all three children died, Henry told police she “placed all of the children in a position on the living room couch as if they were taking a nap.”  The report noted that Henry did not tell the other two adults in the home about what she had done. Police were called to the home later that day.

Henry was then arrested and booked on three counts of first-degree murder into the Fourth Avenue Jail. With no job, and most of her family in Oklahoma, the judge deemed Henry a flight risk and set her bail at $3 million.

Police say they are investigating whether or not postpartum depression played a factor in the killings. 

“Having an increase of hormones when she’s pregnant, then a depletion after birth, and then so quickly another one, and then so quickly another one for someone who’s so young could play such a havoc on the person’s emotional experience because of the depletion of hormones,” psychologist Dr. John Delatorre told AZFamily.

A National Center for Biotechnology Information report estimates that up to 22% of women experience postpartum depression, with psychosis accompanying postpartum in every 1 in 1,000 births. However, Henry’s case is still being investigated.

Fox 10 reached out to Henry’s friends who said they did not think she was capable of murdering her children.

“I never noticed any kind of depression, or anger or hostility toward her children, or anyone else,” said Anthony Repsher, a friend of Henry’s from Oklahoma. “I even had her watch my kids.”

The report did note, however, that Henry allegedly “had a methamphetamine addiction and had been acting strange the past several days.” On Tuesday, during her first court appearance, the county prosecutor explained that Henry’s kids had been removed from her home previously by DCS in Oklahoma.

Henry has an upcoming trial set for Jan. 28.