Baltimore officer aims to convince jurors he did nothing wrong in Freddie Gray's death

FILE - This file photo provided by the Baltimore Police Department on Friday, May 1, 2015 shows William G. Porter, one of six police officers charged with felonies ranging from assault to murder in the death of Freddie Gray. Porter took the stand Wednesday, Dec. 9, 2015 in his own defense. If convicted on all charges, the maximum penalty he faces is about 25 years. (Baltimore Police Department via AP, FILE) (The Associated Press)

FILE - In this Dec. 2, 2015, file photo, Baltimore City police officer William Porter, right, one of six Baltimore police officers charged with the death of Freddie Gray, walks to the courthouse with one of his attorneys in Baltimore. Porter faces manslaughter, assault, misconduct in office and reckless endangerment charges. (Kevin Richardson/The Baltimore Sun via AP, File) WASHINGTON EXAMINER OUT; MANDATORY CREDIT (The Associated Press)

BALTIMORE – More witnesses are scheduled to testify in the defense of one of six officers charged in the death of Freddie Gray, the black man who died after suffering a spinal injury in the back of a police transport van.

Officer William Porter, who is also black, faces manslaughter, assault, misconduct in office and reckless endangerment charges stemming from Gray's death.

Prosecutor say Porter is partially responsible for not calling for a medic when Gray indicated he needed aid, and for failing to buckle Gray into a seat belt.

Porter took the stand for more than four hours Wednesday. He told jurors he didn't call a medic because when he saw Gray, Gray wasn't injured. He also said it's the van driver's responsibility to make sure prisoners in custody are buckled in. Porter wasn't driving the van.

Trial resumes Thursday.