The trial for an officer facing charges stemming from the arrest and death of Freddie Gray after being injured in a police van continues with defense witness testimony.

Officer Edward Nero faces assault, misconduct in office and reckless endangerment charges. His trial began Thursday. Prosecutors finished presenting testimony Monday, and the defense called its first witness, former Baltimore commander and recently retired Charlottesville police chief Timothy Longo.

Prosecutors say Nero and two other officers illegally arrested Gray on April 12 of last year and were negligent when they failed to buckle him into a seat belt. Gray suffered a critical spinal injury in the back of the police van and died a week later. Nero's defense says the officer wasn't involved in Gray's arrest and that it is the wagon driver's responsibility to buckle in prisoners.