The Satan Bug

The Satan Bug is a 1965 American science fiction suspense film produced and directed by John Sturges. The screenplay by James Clavell and Edward Anhalt was loosely based on the 1962 novel of the same name by Alistair MacLean under the pseudonym Ian Stuart. The film stars George Maharis, Richard Basehart, Anne Francis and Dana Andrews. The film score was composed by Jerry Goldsmith.

A mysterious telegram leads Barrett to a nearby hotel where he has a surprise reunion with his old flame Ann, the daughter of his superior, General Williams, who has flown in from Washington to supervise the investigation. Ann reveals she sent the telegram, and that she has been assigned to Barrett as his partner, an arrangement neither minds. At her fathers home, Barretts speculation that a lunatic with a messiah complex is behind the theft is confirmed by a telegram, threatening to release the viruses unless Station Three is destroyed.Barrett and Ann discover another scientist from the station not heard from since the theft is lying dead in his swimming pool. A phone call to the scientists home reveals the name Charles Reynolds Ainsley, a reclusive millionaire crackpot who fits Barretts profile and quickly becomes the focus of the investigation. After a demonstration incident in Florida proves the thieves willingness to use the botulinus, General Williams receives a phone call threatening to release more of the toxin in Los Angeles County unless Station Three is closed. The caller cuts himself off before he can be traced, but not before confirming that he is Charles Reynolds Ainsley. ........

Source: Wikipedia