Six defendants accused in the gang rape of a 16-year-old Northern California girl have pleaded not guilty.

The males, who range in age from 15 to 21, entered their pleas to rape and other charges Tuesday in Contra Costa County Superior Court.

Three juveniles — 15-year-old Cody Ray Smith, 16-year-old Ari Morales and 17-year-old Marcelles Peter — are being charged as adults. The other defendants are Jose Montano, Manuel Ortega and Elvis Torrentes.

Investigators believe as many as 10 people raped the victim, while another 20 or so watched without calling police outside Richmond High School's homecoming dance on Oct. 24.

More on this from KTVU.com.