DALLAS – Former Balch Springs police officer Roy Oliver on Tuesday became the first officer found guilty of murder in Dallas County since 1973.

Watch Judge Brandon Birmingham's reading of the guilty verdict in the video player above.

The jury determined through 13 hours of deliberations that Oliver was guilty of murdering 15-year-old Jordan Edwards in April of 2017. Oliver was found not guilty on two counts of aggravated assault.

The verdict came down about 30 minutes after the jury asked the judge a question about being "split on justification" in the trial. Judge Birmingham urged them to keep deliberating.

Watch: Attorney's reaction to Roy Oliver's guilty verdict

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On April 29, 2017, Roy Oliver fired five shots from an AK-15 rifle into a vehicle carrying several teens, including Edwards and his stepbrother, as they left a house party. Unarmed, Edwards was struck in the back of his head and killed instantly.