MINNEAPOLIS, M.N. (WCBD) – A University of South Carolina (UofSC) School of Law professor on Monday testified in the trial of Derek Chauvin, the former Minneapolis Police Officer accused of killing George Floyd.

Seth Stoughton is a former police officer and professor of Police Law & Policy, Criminal Procedure, Criminal Law, and the Regulation of Vice, according to UofSC School of Law.

Due to his extensive research in police use of force, Stoughton was called as an expert witness by the prosecution.

During his time on the stand, he testified that “no reasonable officer would have believed that it was an appropriate, acceptable, or reasonable use of force” to keep Floyd in the prone position with Chauvin’s bodyweight on his back for nearly 10 minutes.

Stoughton also pushed back against the defense’s claims that Chauvin saw the crowd of bystanders as a threat, saying no reasonable officer would feel that way.

Another key factor, in Stoughton’s eyes, was Chauvin’s failure to render aid once Floyd’s “increasing medical distress became obvious.”

On a whole, Stoughton testified that Chauvin’s actions were not in line with those of a reasonable police officer.

The Associated Press contributed to this report.