Memphis police officers are facing state charges including second-degree murder and aggravated assault in the beating death of Tyre Nichols.

Day four of the Tyre Nichols state trial began with the defense calling more witnesses. Preston Hemphill, a former officer, was first on the stand.

A cybercrime expert with the Tennessee Bureau of Investigation testified Wednesday that a former Memphis police officer charged in the fatal beating of Tyre Nichols took a cellphone photo of Nichols as he sat on the ground,