(CNN) Minnesota police officer Jeronimo Yanez, who's accused of fatally shooting Philando Castile during a traffic stop last July, pleaded not guilty in a St. Paul court Monday.

The killing July 6 became a sensation on social media when Castile's fiancee, Diamond Reynolds, live-streamed its aftermath on Facebook. Reynolds' 4-year-old daughter was also in the car at the time.

Yanez faces trial May 30 in Ramsey County Court in downtown St. Paul. He is charged with second-degree manslaughter , and two counts of dangerous discharge of a firearm.

Yanez said he had no choice in the shooting of Philando Castile

The incident, along with a July 5 fatal police shooting in Baton Rouge, Louisiana, sparked protests and debate about police-community relations.

"That's his right, to plead not guilty," John Thompson, a friend of Castile, said Monday. "It is what it is, we want everything to be fair and just."

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