Delaware prosecutors are calling a use-of-force expert to testify in the trial of a white police officer charged with assaulting a black suspect by kicking him in the head, breaking his jaw.

Former San Jose, California, police officer Ron Martinelli was scheduled to testify Wednesday in the trial of Dover police officer Thomas Webster IV.

Police dashcam video shows Webster kicking Lateef Dickerson in 2013 while Dickerson is on his hands and knees, briefly rendering him unconscious.

Webster's attorney has argued that Webster's actions were justified as he and other officers responded to reports of a fight involving a large group of people and a man matching Dickerson's description armed with a gun.

The defense also plans to challenge Martinelli's qualifications as an expert before he testifies before jurors.