Carl-Fredrik Arndt said he and a friend, Peter, discovered the woman who was attacked by the 20-year-old when they were riding their bicycles on the night of the attack in January 2015.
Ardnt told CBS This Morning: "She was unconscious. The entire time. I checked her and she didn't move at all. The guy stood up then we saw she wasn't moving still. So we called him out on it. And the guy ran away. My friend Peter chased after him."
The grad student and his friend told police they saw Turner on top of the unidentified victim “aggressively thrusting his hips into her.”
The victim has no memory of the incident and in her impact statement, which was read in court, she wrote: "Thank you to the two men who saved me, who I have yet to meet."
She added: “I sleep with two bicycles that I drew taped above my bed to remind myself there are heroes in this story. That we are looking out for one another. To have known all of these people, to have felt their protection and love, is something I will never forget.”
Last week, Turner was sentenced to a mere six months in jail by a California judge.