Gasser said he acted in self-defense when McKnight got out of his SUV and lunged into Gasser's passenger side window.
But prosecutors said physical evidence, including the lack of gunpowder residue on McKnight's body, disputed Gasser's account and showed the two men were farther apart than Gasser has asserted. He is expected to be sentenced on March 15.
Prosecutors said after the trial they were happy with the verdict and that McKnight's family was satisfied as well. "He (Gasser) felt Mr. McKnight challenged him on the bridge", prosecutor Seth Schute told the jury. Jurors began deliberating Friday afternoon and came to a conclusion not long after.
"Authorities say Ronald Gasser, 56, shot McKnight during a (Dec.) 2016 road-rage incident in the New Orleans suburb of Terrytown". It ended with McKnight getting shot as he stood outside Gasser's vehicle at a suburban intersection.
The defense attorney told the jury, "He, meaning Joe McKnight chose to drive like a maniac".More news: United States panel rejects Philip Morris claim iQOS reduces disease risk
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A witness had testified that McKnight weaved in and out of traffic, cutting Gasser and others off, at high speed.
Swaim gave the final rebuttal after defence lawyer Matthew Goetz insisted that his client, a thin, middle-aged man, felt truly threatened by the 28-year-old athlete, who was 6 feet 2 inches tall and weighed more than 200 pounds.
Former Jets and Chiefs running back Joe McKnight was fatally shot by Ronald Gasser in a New Orleans suburb December 1, 2016. He also played a season in the Canadian Football League, spending two games with the Edmonton Eskimos and three with the Saskatchewan Roughriders.
McKnight emerged as a star in his three seasons with USC, rushing for 1,014 yards and eight touchdowns as a senior in 2009. Jefferson Parish Sheriff Newell Normand, who has since retired, angrily denied that race played any role in the case and said a thorough investigation led to the arrest.