A former Philadelphia police officer who shot and killed a motorist during a traffic stop has been acquitted of murder charges by a jury that did convict him of voluntary manslaughter and related counts.

Prosecutors’ sole expert witness in the murder trial of former Philadelphia Police Officer Mark Dial said Tuesday that the fatal shooting of Eddie Irizarry was unjustified — but he said he did not review state law on the permissible use of deadly force by police before forming that opinion.