Detective Sergeant Craig Wait said: "We believe this was a targeted attack on the group of motorcyclists and it’s vital we trace the people responsible. A red Mazda believed to have been involved was later recovered in Ayrshire, but the other vehicles remain untraced. Police are appealing to anyone who was on the M74 near Lesmahagow around the time of the incident. "Were you on the M74 near Lesmahagow yesterday and saw what happened? "Did you see the motorcyclists or vehicles before the incident or the red Mazda and other vehicles leaving the scene?