February 1995
X-Force #43
I have a passing familiarity with X-Men and some of their storylines, but am far from an expert. However, according to this ad, apparently Professor X died in 1994/’95!
Considering that this store is holding a memorial service, it seems like it was a pretty big deal at the time, but did anyone really think he was gone for good? Comic book deaths are so fleeting, especially for main characters – I’m always at least a little suspicious when someone “dies” in a comic.