Arizona shooter Jared Loughner has appeared in federal court in Phoenix, bald and unblinking with a faraway stare.

According to American media, he seemed articulate and calm and said he understood the charges against him.

Loughner’s defence team is led to by the high-profile lawyer Judy Clarke, who will investigate whether an insanity defence would enable him to escape the death penalty.

Clarke previously defended Oklahoma City bomber Timothy McVeigh, who was executed in 2001 for killing 168 people with a truck bomb in 1995.

But state officials said yesterday they wanted to launch their own prosecution against the 22-year-old Loughner.

Because those charges would include the murder of nine-year-old Christina Taylor Green, state prosecutors might have a better chance of securing the death penalty.

Loughner is charged with one federal count of attempted assassination of a member of Congress, two counts of killing an employee of the federal government and two counts of attempting to kill a federal employee.

However, a legal expert said insanity was a a defence that was accepted lightly.

“There will be a mental health defense,” Andrea Lyon, a DePaul University law professor who directs the Centre for Justice in Capital Cases, told the Washington Post. “That may be the only route to go. But the truth is, it is very, very hard to win” on an insanity claim.

The most notable success was John Hinckley Jr., who in 1982 was acquitted by reason of insanity in the attempted assassination of President Ronald Reagan.

Since then, Congress and the courts have made it harder for defendants to win leniency because of a mental condition.

In general, a judge or jury must be convinced the defendant did not understand his acts were wrong.

Meanwhile, comments from former classmates, reinforced by Loughner’s own Internet postings, have created an image of a social outcast with almost indecipherable beliefs steeped in mistrust and paranoia.

Tyler Zuern, who claims he knew Loughner while they attended Mountain View High School in Tucson,  wrote on his Facebook wall:

“I can’t believe a kid I used to chill with turned out to be a cold-blooded murder [sic],” he wrote. “shits fucked up.”

 Another former schoolmate, Gaby Carillo, wrote, “He was weird! Outcast definitely,” while Scott McMullen, another Mountain View alum, posted: “I told u the kid was a fucking wierdo [sic].”

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