'Mob Wives' Natalie Guercio -- Cops Arrested My Boyfriend's Alleged Attacker

The fugitive who allegedly slashed the face of "Mob Wives" star London Rene ... turned himself into NYPD late Tuesday.

London's gf, and 'Mob' co-star Natalie Guercio tells TMZ Rodolfy "Rudy" Lopez was taken into custody after he walked into a Brooklyn police station. Earlier in the day ... police announced Lopez was wanted for the knife attack that went down early Sunday morning.

Natalie says cops called her and London to identify Lopez ... which she says they just did. He was booked for felony assault, reckless endangerment, and criminal possession of a weapon.

TMZ broke the story ... Lopez allegedly jumped London and slashed his face, abdomen, and arm.

Calls to Lopez's attorney haven't been returned.