One of the victims had welts and bruising on his chest, buttocks and back, police said.
The alleged striking of fraternity pledges with a wooden paddle has led to hazing charges against five University of North Texas students.
UNT deputy police Chief Ed Reynolds says the October case involving 12 pledges has been forwarded to the district attorney's office.
The school in Denton has suspended the Kappa Alpha Psi fraternity pending results of the investigation. An affidavit says the hazing happened on or around Oct. 10, in which at least one victim had welts and bruising on his chest, buttocks and back.
The Denton Record-Chronicle reports two students originally were charged last month with hazing, causing severe bodily injury, then three more students were charged.
University spokeswoman Deborah Leliaert says the matter will also be reviewed by the UNT Center for Student Rights and Responsibilities.