Carl-Fredrik Arndt is a Swedish quantitative researcher. He is one of the two graduate students who rescued Chanel Miller and played a role in the arrest of Brock Turner.

Carl is originally from Karlskoga, Sweden. ^{[1] [2]} He earned his Ph.D. student in Computational and Mathematical Engineering from Stanford University.

Before that, Carl studied Economics and earned his Bachelor's degree at Linköping University. He also received a Master's degree in Applied Physics and Electrical Engineering from The Institute of Technology at Linköping University. He also completed an exchange program at Stanford before starting his PhD there. ^[1]

Carl most recently worked as a quantitative research summer associate at J.P. Morgan & Co. in 2015. He has worked as a quantitative analyst at RGM Advisors LLC, Ampfield Aktiebolag, and Thomson Reuters. ^[1]

He is currently a quantitative researcher at Two Sigma, a New York City-based hedge fund.^[1]

Carl-Fredrik Arndt and his friend saved a woman from a rapist, Brock Turner. Carl and his friend Peter Jonsson tackled and restrained Turner until police arrived after they saw him raping an unconscious woman in May 2015.

Carl and Peter Jonsson were cycling to a party on the Stanford campus when they saw Brock Turner on top of his victim behind a dumpster.

Carl and Peter approached Turner since they saw that the woman was not moving at all.

When they started to talk to Turner and he got up they realized that the woman was completely still.

When Turner tried to run away, Peter ran after him and tackled him, while Carl checked to see that the unconcious victim was still alive.

Carl and Peter then restrained Turner and called the police.

They held down the then-19-year-old swimmer until the police arrived.

Carl and Peter gave their reports to police and acted as important witnesses in the trial.

The victim, Chanel Miller, said that she was forever grateful to Carl-Fredrik Arndt and Peter Jonsson. She wrote in her letter the following thanking them: