Cross-dressing killer is a lady wrestler!

Holy crap!

The cross-dressing murderer who terrorized Mexico City's old ladies for three long years is actually a female wrestling star.

Mataviejitas -- the "Little Old Lady Killer" - brutally murdered more than 40 defenseless old women, four of them this month alone.

Now cops say they've got the killer: a 48-year-old former Mexican wrestling star who is a woman herself.