WHO KILLED JAMES MICHAEL GARDNER?

At the link https://www.tapatalk.com/groups/zodiackillerfr/james-michael-gardner-august-7-1968-t6595.html there is the article about the death of James Michael Gardner, a man from Santa Ana who was riding along the San Diego Freeway in Fountain Valley near the Ward underpass. The victim was hit by a barrage of 22 or 25 caliber bullets. The events occurred on August 7th, 1968