X-Men Noir #1

"The coroner's men flipped the redheaded corpse over so Dukes and Magnus from Homicide could get a better look at her. 'Better' being a relative term in this case, with the claw marks that slashed her face into a featureless, bloody mask and turned her guts into a butcher shop explosion. "But the tattoo -- the simple, encircled 'X' above the left shoulder blade -- remained intact, and Dukes pointed it out with the toe of his wingtip once Peter the rookie was done heaving up lunch. "'See this ink?' he said. 'Means she did time at this reform school upstate, run by this shrink, Xavier...'"