Before he allegedly went on the deadly shooting rampage in Tucson, Jared Loughner considered every aspect of the assault including the likely punishment, sources tell ABC News.
Loughner, 22, used his home computer to browse a website with information about the effects of lethal injection, according to sources familiar with the investigation. He appeared to want to know what death by injection felt like, the source said.
Lethal injection is the method of capital punishment imposed by the federal government.
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Loughner also allegedly browsed the Internet for information about solitary confinement and, perhaps more disturbingly, an official said, he had been researching political assassins.
It all paints a dark picture of cold-blooded forethought, sources said, and an obsession with assassinating Rep. Gabrielle Giffords, D-Ariz., who was shot in the head but survived the attack.
Police previously have released details about items confiscated from Loughner, including notes with the words, "I planned ahead," "Giffords," and "my assassination."
Six died and several others, including Giffords, were injured in the Tucson attack on Jan. 8. The congresswoman now is recovering in a Houston brain rehabilitation hospital.
Some legal scholars believe the new evidence makes the insanity defense, which already was considered a long shot for success, even more difficult for Loughner.
"The extent to which he planned the shootings makes it seem inconsistent with someone who doesn't know what he's doing or doesn't know right from wrong," said Stephen Saltzburg, a former senior Justice Department official.
Earlier this week, Loughner appeared in a courtroom with a constant smile on his face, pleading not guilty to the five federal charges against him -- one count of attempted assassination of a member of Congress, two counts of killing an employee of the United States and two counts of intent to kill employees of the United States.
Legal scholars say he has left his defense attorneys with severely limited options.