An upstate sicko cut off his electronic monitoring bracelet before carrying out a savage crime — stabbing a school librarian to death and raping a 10-year-old girl, cops said.
Investigators were probing Saturday how 29-year-old David Renz, who was previously charged with possessing child pornography, managed to disable his monitoring device.
Renz, a computer whiz, has already faced jailhouse justice in the wake of his sickening crime — suffering a broken nose in a prison fight.
He was beaten inside a holding cell at the Onondaga County Justice Center on Friday — a day after the attack.
Cops say Renz abducted 47-year-old Lori Bresnahan and the girl as they left a gymnastics class at a mall outside Syracuse late Thursday.
