Valerie Castile, mother of Philando Castile, speaks out during a news conference on Friday. A Minnesota police officer was cleared Friday in the fatal shooting of Philando Castile.

ST. PAUL, Minn. — A Minnesota police officer was cleared Friday in the fatal shooting of Philando Castile, a black motorist whose death captured national attention when his girlfriend streamed the grim aftermath on Facebook.

Castile’s family stormed out of the courtroom after the verdict was read, and the city of St. Anthony swiftly announced plans to dismiss Officer Jeronimo Yanez, despite his acquittal. Yanez was charged with manslaughter in the death of Castile, a 32-year-old school cafeteria worker, during a July 6 traffic stop that turned deadly seconds after Castile alerted the officer that he was carrying a gun. Castile had a permit for the weapon.

“The fact in this matter is that my son was murdered, and I’ll continue to say murdered, because where in this planet (can you) tell the truth, and you be honest, and you still be murdered by the police of Minnesota,” his mother, Valerie Castile, said, referring to the fact that her son was shot after he volunteered to Yanez, “Sir, I have to tell you, I do have a firearm on me.”

“He didn’t deserve to die the way he did,” Philando Castile’s sister, Allysza, said, through tears. “I will never have faith in the system.”

Thousands of people gathered Friday evening at the nearby state Capitol to protest the verdict, and began a march. The mixed-race crowd, including many people with children, carried signs that read “Unite for Philando” and “Corrupt systems only corrupt.”

The protest was peaceful as darkness fell, but a smaller group splintered off and walked down an entrance ramp to block Interstate 94, quickly snarling traffic and leading to the freeway’s shutdown in both directions. A police line confronted marchers down the highway, but after a standoff of more than 90 minutes, the group dwindled and appeared to largely clear the interstate without police using force.

Jurors deliberated for about 29 hours over five days before reaching the verdict. Prosecutors argued that Yanez had overreacted and that Castile was not a threat. Yanez testified that Castile was pulling his gun out of his pocket despite his commands not to do so. The defense also argued Castile was high on marijuana and said that affected his actions.

Yanez stared ahead with no reaction as the verdict was read. Afterward, one of his attorneys, Tom Kelly, said the defense was “satisfied” and “felt all along his conduct was justified.”

“However that doesn’t take away from the tragedy of the event,” Kelly added.