Police say Julie Powers Schenecker, 50, shot and killed her kids because they were talking back and "mouthy." Investigators found the soccer mom drenched in blood on Friday on the back porch of the family's upscale home.
Investigators said 16-year-old Calyx and 13-year-old Beau had each been shot twice in the head a day earlier - Beau in the family's car on the way to soccer practice, Calyx in her room as she studied at her computer.
Both teens were killed with a .38-caliber pistol, which authorities say Schenecker bought five days earlier.
According to a report released Monday, Calyx told police in November she had been hit by her mother on several occasions. On Nov. 6, Calyx called police and told officers her mother hit her as she drove home in the family car.
According to the report, Calyx admitted saying something she shouldn't have that angered her mother. Then, her mother proceeded to hit her with an open hand for about 30 seconds. The girl told officers that she was not usually hit - she was disciplined by getting her privileges and belongings taken away from her.
Two days later, Schenecker was in a car crash not far from her Tampa home. She was cited for careless driving. She was apparently going 70 mph in a 55-mph zone and crashed into a trailer hauling landscaping equipment.
Officers on the scene wrote that Schenecker "showed signs of drug impairment," including dilated pupils with no reaction to light and "mush-mouthed speech."
Other field sobriety tests weren't conducted because Schenecker was taken to the hospital. Another trooper went to the hospital to obtain a blood sample from Schenecker, but she had checked out by then.
Schenecker was ordered held without bail Monday during a brief court hearing on Monday. She did not speak - though she did cry and hold a tissue, her hands bound by handcuffs. She is in the Hillsborough County Jail on two first-degree murder charges.
Schenecker's husband, Parker, is an intelligence officer who was working in the Middle East when the shootings happened. Neither of them had a criminal record.
The family moved to Tampa in 2008 when Parker Schenecker was transferred to U.S. Central Command headquarters, which oversees the Iraq and Afghanistan wars and is housed at MacDill Air Force Base.
The Associated Press contributed to this report.