....there are right-wing crackpots on the loose:

Some conspiracy Web sites are claiming that the shootings that nearly
killed Representative Gabrielle Giffords and did end the lives of a
federal judge, a 9-year-old girl and four others never actually took
place. One particularly bizarre site, run by a Texas man, says it was
all a government hoax that used actors.

Such obviously fantastic claims would usually not merit the attention of
law enforcement, but they have in this instance because some believers
have been confronting, and alarming, some of the people associated with
the case in recent weeks. [...]

....One shooting victim said he notified the F.B.I. recently after two
men showed up at his Tucson home claiming to be investigators and saying
they were trying to determine whether the shooting was a hoax.

“They tried to get into my home,” said the victim, who asked that he not
be identified because it might attract more such visitors. “They wanted
to know if I had any pictures. They said they didn’t believe the event
took place.”

The victim said that when he pressed the visitors for identification,
one of them presented a business card that listed the Texas conspiracy
site, which describes the shooting as an exercise conducted by the
Department of Homeland Security. Other people connected to the case,
including hospital personnel, victims’ relatives and possible trial
witnesses, have received similar visits or seen their images on the Web
site, officials said.

From the NY Times..