On Saturday morning outside a grocery store in Tucson, Ariz., a gunman shot Rep. Gabrielle Giffords, D-Ariz., as well as federal judge John M. Roll and 17 others. Giffords, shot through the head, made it through neurosurgery and remains in critical condition. Roll is dead, as well as five others, including a 9-year-old girl.

According to Giffords spokesman C.J. Karamargin, three of the congresswoman's staffers were shot. Gabe Zimmerman, Giffords' director of community outreach, died, while the other two, who were not yet identified, are expected to survive.

Two bystanders tackled the alleged gunman, Jared Loughner, 22, who is now in custody.

Giffords, who was attending one of her "Congress on Your Corner" events with her constituents outside the Safeway store, was the target of the suspected shooter, according to authorities.

At a news conference Saturday night, Pima County Sheriff Clarence Dupnik said that authorities believe that the suspected shooter did not act alone and that they are seeking a white male in his 50s.

The suspected shooter's motives are unknown. Giffords had been harshly criticized in the past year over her vote for healthcare reform, and vandals either kicked or shot out windows of her Tucson office right after the vote. Still, assassination attempts on members of Congress are rare, and no members typically have security details except those in leadership.

Roll, the chief U.S. District judge in Arizona who was killed, had also received numerous threats beginning in 2009 for agreeing to hear a case that illegal immigrants had brought against an Arizona rancher. But according to witnesses, the gunman shot Giffords first, so Roll, who was appointed to the federal bench by President George H.W. Bush in 1991, may not have been the chief target.

Media trawled through Loughner's social media profiles, sites that haven't necessarily been verified as his, finding little to show his political persuasion other than plain crazy. His alleged YouTube page lists Mein Kampf and The Communist Manifesto among his favorite books. Giffords is Jewish. The online profile associated with Loughner also insisted that the United States must back its currency with gold or silver, and said he "won't trust in God."

Caitie Parker, a 22-year-old who said she went to high school and college with Loughner, posted on Twitter, "As I knew him he was left wing, quite liberal. & oddly obsessed with the 2012 prophecy."

Still, political pundits didn't hesitate to point fingers. Liberal blogger Mark Kos tweeted, "Mission accomplished, Sarah Palin." After the healthcare debate, Palin had posted a controversial map putting sharpshooter sights over districts represented by lawmakers who had voted for the healthcare law-including Giffords. Palin posted her condolences to Giffords on her Facebook page Saturday, and the sharpshooter map is no longer online.

DeAnn Hatch, the co-founder of the Tucson Tea Party who campaigned furiously against Giffords in her recent tight election, condemned the attack. "I want to strongly, strongly say we absolutely do not advocate violence," she told The New York Times. "This is just a tragedy to no end."

Liberal MSNBC pundit Rachel Maddow tweeted, "There is nothing to be gained from speculating on the motives and affiliations of AZ shooter w/o facts."

Speaking from the White House late Saturday afternoon, President Obama said, "We are still assembling all the facts. . . . We don't yet know what provoked this unspeakable act."

Obama, who dispatched the director of the FBI, Robert Mueller, to Arizona to lead the investigation into the shooting, added, "We are going to get to the bottom of this, and we're going to get through this."

Members of the House of Representatives expressed grief and fierce anger. House Speaker John Boehner said he was "horrified," adding, "An attack on one who serves is an attack on all who serve." House Minority Leader Nancy Pelosi called it a "national tragedy."

Fellow Arizonan Sen. John McCain was particularly forceful: "I beg our loving Creator to spare the lives of those who are still alive, heal them in body and spirit, and return them to their loved ones. Whoever did this, whatever their reason, they are a disgrace to Arizona, this country, and the human race, and they deserve and will receive the contempt of all decent people and the strongest punishment of the law."

Giffords is a Blue Dog Democrat who is a strong supporter of gun rights. On the first day of the new Congress she refused to vote for Nancy Pelosi to be her party's minority leader, casting a vote for civil rights icon Rep. John Lewis, D-Ga., instead.