Time bomb

"It was some time before anyone was able to detect any pattern at all in the bomb explosions, but Lieutenant Danforth of the bomb squad of the IllinoisSecret Police finally did. Each time, bigwigs of the fanatic Sons of America movement were the victims, the bombs exploded only in a restricted area, and always on a rainy night.

Many thought that time travelers were at work, moving through space and time and committing their crimes before the event. Mr. Ramsey, telepath-in-residence of the Illinois State Police Force said this was impossible. But even his powers were strained by Danforth's discovery of the very strange Gilbert and Shirley Nash, who surely had some weird - and possibly evil-abilities."--Publisher desccription.