The Lost Summer by Ernie Moulton

George Mictackic leads an investigative group and they decide to take a summer break and visit an island off the coast of Nicaragua for a vacation. Before they could leave, for the island, they are surprised by an intruder who happens to be wanted for murder. Then on the road, a semi-truck clips the car causing a crash, and everyone in the car is injured. After their recovery, one girl and then another is captured by the man supposed to be in prison. That summer is lost.