Loughner pleads guilty to 19 counts in Tucson, Arizona, mass shooting

TUCSON, Arizona (CNN) -- Jared Lee Loughner, the alleged gunman in last year's mass shooting outside an Arizona supermarket in Tucson that killed six persons and wounded then-U.S. Rep. Gabrielle Giffords, pleaded guilty Tuesday to 19 charges in exchange for the government not seeking the death penalty.

Earlier Tuesday, Judge Larry Alan Burns found Loughner competent to stand trial in a federal court in Tucson.

Walking with a bit of a slouch, Loughner cast a sneer at the packed gallery when he entered the courtroom. During the guilty plea proceedings, the gallery was quiet, with some people sniffing and wiping away tears.

CNN's Kyung Lah and Michael Cary, both in Arizona, and Bill Mears contributed to this report.