Death Comes on Silver Wings — Robert W. Gregg

A small pontoon plane crashes into the waters of Crooked Lake one beautiful summer morning. The pilot is dead, and the sheriff turns the case over to a federal agency that rules the pilot died of a heart attack. But the sheriff is puzzled by the strange behavior of the people mourning his death. In the course of their investigation, Carol and Kevin discover that the pilot's medications have been mysteriously switched, that his survivors are engaged in a nasty fight over a will, and that his doctor may be guilty of malpractice. Will the killer strike again?