When police responded to a call from a concerned relative and found Julie Schenecker on the back porch of her Tampa home, they said she was covered in blood and made a gut-wrenching admission: She had killed her teenage son and daughter because they were "mouthy."
Police said the military officer's wife, described by her mother as depressed, shot and killed her son on the way to soccer practice, then drove to their upscale home and shot her daughter in the head while the girl studied at her computer.
"I think we will never understand how or why a mother could take the lives of her children," police spokeswoman Laura McElroy said. "That was the only reason she provided to our detectives."
Schenecker was charged with two counts of first-degree murder. Wearing a white jumpsuit, she was led into a county jail on Friday, shaking and being supported by a sheriff's deputy.
Authorities said Schenecker was taken early Saturday, shortly after midnight, to Tampa General Hospital shortly after midnight to be treated for a medical condition that existed before she was taken to jail.
Now authorities are trying to understand what triggered the killings.
Schenecker's mother had called police from Texas at about 7:40 a.m. Friday because she was unable to reach the 50-year-old woman, whom she said was depressed and had been complaining about her children.
McElroy said Schenecker left a note detailing her plans to kill her children and then herself, saying "they talked back and were mouthy and that she was going to take care of it." She provided the same motive to police who interviewed her, authorities said.
After being advised of her right to remain silent and consult an attorney, "the suspect confessed to killing her two children," police said in a statement. "She described the crimes in detail."
Schenecker's husband, Army Col. Parker Schenecker, is stationed at the headquarters of U.S. Central Command at MacDill Air Force Base in Tampa. The father had been away for several days, said CentCom spokesman Lt. Col. Michael Lawhorn, describing him as a career Army intelligence officer.
Police said Parker Schenecker was in Qatar and was told of his children's deaths on Friday.
Officers found the body of Schenecker's daughter, Calyx Schenecker, 16, in an upstairs bedroom, McElroy said. The body of her son, Beau Schenecker, 13, was found in a sport utility vehicle in the garage.
An arrest affidavit said Schenecker shot her son twice in the head "for talking back" as she drove him to soccer practice Thursday night. She drove home, went inside and shot her daughter in the back of the head while the teen sat at a computer doing homework, then shot her in the face, the affidavit said.
McElroy said investigators believe the teens "never saw it coming." Both were killed with a .38-caliber pistol. Police said the weapon was purchased five days earlier, The Tampa Tribune reported.
The family's home is on a cul-de-sac in a gated country club community in north Tampa.
Charanun Soodjinda, 38, lives across the street. He said the Scheneckers moved in about two years ago and "fit right in." The couple's two children often played in the cul-de-sac with other neighborhood kids, and Julie Schenecker seemed to be at home a lot.
"They seemed like a nice family," Soodjinda said. "I never thought this would happen. How could you do that to your children?"
Seena Jain, who carpooled with the Schenecker children and her own daughter, Sheema, 15, told the St. Petersburg Times that recently Parker Schenecker had picked up his wife's carpooling shift while she recovered from a serious car crash that happened about a month ago. Details of the accident weren't immediately available.
The Times also reported that the Department of Children and Families said it investigated a complaint involving the family about two months ago, but that the tip was determined to be unfounded and the case was closed. Agency spokesman Terry Field told the paper he could not elaborate.
Media outlets described the students as active at school, with Beau playing soccer at Liberty Middle School and Calyx in the pre-International Baccalaureate program at King High School, where she ran cross-country and started a Harry Potter fan club.
Sylvia Carroll, who attended Muscatine High School in Iowa with Julie Schenecker, said she was a popular and athletic student who excelled in basketball in the late 1970s. They reconnected about a year ago on Facebook.
"I'm just in shock," said Carroll, who now lives in Austin, Texas. "I can't believe this."
Associated Press writers Christine Armario and David Fischer in Miami contributed to this report.