Former Rep. Gabrielle Giffords, who survived an assassination attempt in 2011, reacted to Wednesday's school shooting massacre in a series of emotional tweets that called on politicians to do something to help stop gun violence.
A Democrat, Giffords represented Arizona in the House from 2007-2012. She has since become an advocate for gun control.
Police said a 19-year-old former student opened fire at Marjory Stoneman Douglas High School in Parkland, Florida. Seventeen people were killed and several others were injured.
The shooter was able to escape the school afterward but police captured and arrested him a short time later.