Hello CementPizza,
There are no authenticated reports of any fatal attacks on people committed by squid. In the 1991 movie "Mission of the Shark," about the 1945 sinking of the
U.S.S. Indianapolis, the film's creators made the wholly unsupported claim that Navy crewmen were attacked by squid. There was also a documentary about sea monsters, hosted by Arthur C. Clarke, in which the late Dr. Frederick Alldrich made the (again) wholly unsupported claim that survivors of a transport sunk off the coast of Newfoundland had been attacked by giant squid. Peter Benchley told a similar tale in his squid novel "Beast," but, again, there's no proof that anything of the sort ever happened.
Dosidicus gigas, the "jumbo squid," is a very aggressive animal, and several of them grabbed an underwater cameraman some years ago during a night dive off Baja. (Joel, I think it was Alex Kerstitch...not sure about the spelling of his last name) Mexican fishermen who ply those waters are justly worried about falling into the water with them, but there haven't been any authenticated maulings or fatalities. Put simply: if it ain't on film or in the science journals, it's purely anecdotal.
There is a famous tale of a giant squid,
Architeuthis dux, that "attacked" a small boat off Newfoundland in 1873/74. The occupants had approached the (presumably) unhealthy animal while it floated on the surface, poked it, and were surprised to find it still alive, whereupon it grabbed the vessel and struck the gunwhale with its beak. One of the occupants chopped off a tentacle, which served as proof of the encounter. For a full account of the incident and its various retellings, you and your friend might check out "The Search for the Giant Squid," by Richard Ellis (available in paperback from Penguin books).
It's possible that a big squid could kill a human. A few species are big and aggressive enough to pull it off, but they would not have many occasions on which to do so. The current and unusual presence of large numbers of aggressive jumbo squid off the western coast of the U.S. does make me wonder if a surfer might not get nipped in the near future, but that's just my own bloody-minded fantasy.
Thanks for posting. There's a ton of information here about these animals. Hope you find much of interest.
Cheers,
Clem