Philadelphia Police: Giants Jersey On Rocky Statue ... 'Crime Against Humanity'

WARNING -- Whoever put the NY Giants jersey on Philly's famous Rocky Balboa statue better watch his/her ass ... 'cause the Philly PD is calling the situation a "CRIME AGAINST HUMANITY!"

Ok, so there's no statewide manhunt for the perp or anything like that ... but people in Philly were FUMING after some G-Men fan trolled the city before tonight's Eagles vs. Giants game.

We spoke to the Philadelphia Police Dept. about the situation and the public affairs office told us, "We are aware. There's no video, no surveillance, where we could actively search for who did this."

On whether it was a crime, we were told -- "I'm not sure it's a crime. It's a crime against humanity!"

"As far as us actively investigating, no one has reported it. We're not treating it like a crime. If they wrote on it, spray painted it, that'd be a different story."