A police officer charged with manslaughter in the death of Freddie Gray took the stand Tuesday and began testifying in his own defense.

Officer William Porter, the first of six officers to go on trial in Gray’s death, also faces assault, misconduct in office and reckless endangerment charges. If convicted on all of the charges, the maximum penalty he faces is about 25 years.

Prosecutors have argued that Porter should be held partially responsible for Gray’s death because the officer didn’t buckle the man into a seat belt when he checked on him in the back of a transport wagon, and he failed to call for a medic when Gray indicated he needed medical attention.

Read more at JETMag.com.