Published: Feb 10, 2011 7:19 PM EST
Updated: Feb 10, 2011 4:22 PM EST

TAMPA- A grand jury has indicted a Tampa mother accused of killing her two children.

Julie Schenecker was indicted on Thursday. Police say the 50-year-old woman bought a .38-caliber revolver the weekend before the shootings.

The St. Petersburg Times has reported she wrote a note before the Jan. 27 shootings in which she referred to her plan as a "massacre."

Police have alleged Schenecker shot her children, 16-year-old Calyx and 13-year-old Beau, for being "mouthy."

She faces two felony charges of premeditated first-degree murder.

Her arraignment is set for Feb. 16.

--- Information from: St. Petersburg Times, http://tampabay.com

(Copyright 2011 by The Associated Press. All Rights Reserved.)