Rep. Gabrielle Giffords remained heavily sedated and in critical condition today as investigators sought to understand what motivated a gunman to carry out an assassination attempt on the Democratic lawmaker in a rampage that killed six. A University Medical Center spokeswoman said that Giffords underwent a two-hour surgery yesterday and has not been conscious since the shooting. More information is expected at a news conference.
Pima County Sheriff Clarence Dupnik, meanwhile, confirmed that a second suspect was being sought. Officials released a security camera image of a 40- to 50-year-old white man with dark hair who had been seen in the area. (Read more Jared Lee Loughner stories.)