A Phoenix woman stabbed her three young sons to death and put their partially dismembered bodies in a closet before she tried to kill herself at their home, police said Thursday.

Officers found the dead boys — ages 2 months old and 5 and 8 years old — in a closet full of miscellaneous items. The youngest boy's body was in a case of some kind in the closet, Sgt. Trent Crump said.

No identities were released.

"Detectives have informed me that it appears the children at this point were likely stabbed to death and parts of their bodies were dismembered," Crump said.

He did not elaborate on the dismemberment but earlier said it was an "absolutely horrific scene."

The woman's brother called 911 early Thursday morning after his sister stabbed herself some time after he returned from work to their northwest Phoenix home late Wednesday night, police said.

The woman initially spoke with her brother in the garage but then locked him out of the house and then locked herself in a bedroom once he'd forced his way into the home, Crump said.

She then came out all bloody, having stabbed herself, and she tried to drown herself in a bathtub while the brother was getting towels for her bleeding, the sergeant said.

That's when the brother called 911 and police responded.

After dealing with the badly injured woman, officers didn't discover the boys' bodies until they started searching the whole home, they said.

As she was being taken to the hospital, the woman told police her sons were staying with a baby sitter, and the brother told police the boys did regularly stay with that person, Crump said.

The mother was hospitalized in critical condition with neck and abdomen wounds but is expected to survive, police said.

"She will be in the hospital for some time with some very serious self-inflicted injuries," Crump said. "It's a murder investigation at this point."

When the brother returned home from work, his sister met him in the garage and talked about religion and the meaning of life, which he told police was a recent subject of interest to her, he said.

The brother told police he didn't understand why his sister recently had started talking about religion, and family members "don't know what set this off," Crump said, referring to the killings.

The woman and her children live with her brother and the siblings' mother, Crump said. "There's no father in the picture."

Residents said the neighborhood of townhomes is quiet, and the older boys frequently rode bicycles outside.

"Kids are supposed to feel good in this neighborhood," said Frank Segura, who lives across the street. "It's heartbreaking. They're just nice kids."

Next-door neighbor Shelley Severns said her children played with the older boys, whom she called "cute little things."

"I'm still processing all of this. It's very tragic because you don't know why this happen," Severns said.

The boys were killed sometime during a several-hour period after the woman's mother left for work Wednesday evening, Crump said.

Crump said police had unconfirmed information that the woman might have been pregnant. "It may have been a reason why she had self-inflicted stab wounds" in the abdomen, he said.

He said police were unaware of any documented history of mental illness.