Officer Joanna Grivetti said the girl, who was 16 at the time of the attack, had fresh abrasions on her back, face, ears, knees, tops of her toes and toe knuckles.
"I do believe the injuries to the top of her feet were because she was dragged upon a surface," Grivetti said.
But a lawyer for one of the seven defendants questioned whether the injuries could have been caused by the girl as a result of her being intoxicated.
"This person could have been intoxicated and fell to the floor on her knees...Given that there was testimony yesterday that this could have been consensual, she could have been on her hands and knees trying to get up because she was intoxicated," attorney Ernie Castillo who is representing 17-year-old Ari Morales said.
Senior Deputy District Attorney Dara Cashman said medical records will cast aside any doubts.
"It is fair to say that critical was putting it minor. I mean, she had injuries that were life threatening," she said.
The two minors have been charged as adults, six of the seven suspects face life in prison and one faces 26 years in prison for aiding in the rape.
In the third day of the preliminary hearing, Grivetti listed the evidence collected at the scene of the attack, which included multiple empty alcoholic beverage containers, including a can of Four Loko, empty condom wrappers and a woman's stocking still attached to a silver high-heeled shoe.
Gravetti was disturbed and took a long pause when she was asked to describe a photograph of one particular piece of evidence collected.
"This is a pair of white, cotton, girl's underwear," Grivetti said.
Judge Gregory Caskey ruled, however, that much of her testimony will be stricken from the court record after defense attorneys objected to the officer being considered an expert on wounds.