Julie Powers Schenecker: Cops Say Fla. Mom Accused of Killing Her Kids Called Plan a "Massacre"

(CBS/AP) Investigators say Julie Powers Schenecker, the Florida mother accused of killing her teenage daughter Calyx and son Beau "for talking back" too many times, wrote a note before the shootings in which she referred to her plan as a "massacre."

PICTURES: Julie Powers Schenecker Kids

Authorities say the 50-year-old Tampa mother bought a .38-caliber revolver the weekend before the shootings. Tampa police spokeswoman Laura McElroy told the St. Petersburg Times the mother also observed that the three-day waiting period to take a gun home would "delay the massacre."

According to an arrest affidavit, Schenecker shot her 13-year-old son Beau in the head twice "for talking back" while they were in the family car on their way to his soccer practice. The report said Schenecker then returned to their upscale home and shot 16-year-old Calyx in the face while the girl studied at her computer.

Her husband, Army Col. Parker Schenecker, is in Fort Worth, Texas, for Tuesday's funeral for the children.

Schenecker is charged with first-degree murder, but her arraignment has not yet been scheduled.

COMPLETE COVERAGE OF JULIE POWERS SCHENECKER ON CRIMESIDER