The woman was sitting in her living room covered with blood when police arrived Monday. Her nearly 11-month-old daughter lay fatally injured in a crib in a bedroom of the family's apartment in Plano. The child died shortly afterward at a nearby hospital.
Police have charged the 35-year-old mother with capital murder, but declined to reveal where she is being held.
Schlosser, who had a history of postpartum depression, had been investigated on child neglect allegations earlier this year, but Texas Child Protective Services had recently closed a seven-month investigation, concluding that Schlosser did not pose a risk to her children.
Neighbors said she seemed to be a loving, attentive mother.
"It's hard to believe," neighbor Al Sosa told CBS station KTVT.
"I don't feel real comfortable here," said neighbor Michael Lujan. "I understand that women become depressed at that time, yeah, but you don't kill your kids because of it."
On Monday, authorities discovered a grisly scene at the family's apartment after the child's father called a day-care center, and asked them to check on his wife and daughter.
Day-care workers called 911 after talking to the mother; an operator then called Schlosser.
Asked if there was an emergency, Schlosser calmly responded "Yes," according to 911 tapes released by police.
"Exactly what happened?" the 911 operator asked.
"I cut her arms off," Schlosser replied, as the hymn "He Touched Me" played in the background.
"You cut her arms off?" he repeated.
"Uh huh," she answered.
It was not immediately clear what instrument was used to sever the baby's arms or why the child's father called a day-care center to check on his family.
"The police officer went into the apartment and found an 11-month-old baby in a back bedroom with both arms severed," said police officer Carl Duke.
"I've been with the Plano Police Department 17 years, and I've never experienced anything like this — and would not want to," said police spokesman Bryan Wood. "Anytime an officer sees something like this, it affects you."
Schlosser lived at the apartment with other family members, including her two older daughters. Authorities said the girls, ages 6 and 9, were at school when police arrived, and that their father was at work.
Children's bicycles rested near the entrance to the family's apartment in suburban Dallas, along with angel garden statues.
Child Protective Services is now conducting an internal investigation to make sure case workers made the right decision in this case, reports KTVT's Jack Fink.
"There were never any indications of violence with this family," agency spokeswoman Marissa Gonzales said. "The children had always been healthy, happy and cared for."
Neighbors said Schlosser took her children swimming in the summer, had picnics in the courtyard and walked her baby around the complex the same time each afternoon.
Dena Livingston, 43, said she saw Schlosser making her rounds with the stroller on Sunday. Two days earlier, she saw Schlosser waiting with the baby outside the elementary school where her two other daughters attend.
"She didn't give off like she was in a distant world or didn't care about the baby," Livingston said.
Livingston's husband, Brad, added: "To see her with the girls, you would just think she was a great mother."
Child-protective officials were interviewing Schlosser's daughters and would talk to the father before deciding whether to remove the girls from the home.
In January, the agency was called to the home after Schlosser was seen running down the street, with one of her daughters bicycling after her, authorities said. When officials arrived, the child told them her mother had left her 6-day-old sister alone in the apartment.
Schlosser appeared at the time to be suffering from postpartum depression and having a psychotic episode, Gonzales said.
Schlosser was hospitalized, and later agreed to seek counseling and saw a psychiatrist, Gonzales said.
"At the time we closed the case, we had been assured that Mom was stabilized and that she was not a risk to herself or her children," Geoff Wool, spokesman for the Family and Protective Services Department, said.
The Schlosser case is the latest infamous case in recent years of Texas mothers accused of killing their children.
Andrea Yates of Houston drowned her five children, ages 6 months to 7 years, in the bathtub in 2001. She was convicted of capital murder in the deaths of three of the children and is serving a life sentence. The defense had said she suffered from schizophrenia and postpartum depression.
This year, Deanna Laney, 39, was acquitted of capital murder by reason of insanity after killing her sons, ages 8 and 6. A third son was injured. Psychiatrists said Laney suffered from psychotic delusions that God told her to kill her children. She was committed to a mental hospital.