(Some Spoilers) Sweeping into New York City on a first-class railroad car a killer who doesn't kill with a gun or knife or club but just with his,or it's, touch and breath. A killer that's as old, or even older, then man himself. That killer has a name it's know the world over as smallpox.<br /><br />Arriving in New York one cold November afternoon the killer hidden inside of Sheila Bennet, Evelyn Keyes, and like a Trojen Horse it waits until the opportunity presents itself. Then like a ticking time bomb with it's fuse set off explodes throughout the length and breath of the city.<br /><br />Sheila knows that she's being followed by a U.S Customs officer who's been on her tail since she came back to the US from the Island nation of Cuba. Having smuggled $50,000.00 of illegal uncut diamonds she had to be careful in getting them to her husband Matt, Charles Korvin, to be cut and sold to unsuspecting jewelers in the city. <br /><br />Mailing the diamonds ahead of time Sheila knows that if caught the diamonds won't be found on her. What she doesn't know is that Matt is two timing her by having an affair with her kid sister Francie, Lola Albrght. Even worse he plans to check out of town with the diamonds leaving her as well as Francie holding the bag.<br /><br />Even though we know right from the start of Sheila's deathly condition it doesn't really come to the surface until much later in the movie.The first half of "The Killer that stalked New York" is a crime suspense/drama with the U.S Customs officials and NYC police looking for the stolen diamonds. As Sheila starts to get sick and begins to infect everyone whom she comes in contact with the film reaches the point of a mass panic in the streets type horror movie. <br /><br />Both the police and custom officials together with members of the city's Health Depertment race against the clock to find Sheila before she infects the entire city of New York with the deadly smallpox infection that she's carrying. Sheila finding out from Matt's boss Willie Dennis,Jim Backus,that he quit his job as a nightclub piano player and that he was having an affair with Francie shocks her into the realization to what a heel he is.<br /><br />Confronting Francie at her apartment it turns out that Matt not only stiffed Shelia but her sister as well. Which later leads the guilt-ridden Francie to take her own life. On the run and not knowing that she's infected with smallpox Sheila goes to her brother Sid (With Bissell),who manages a flop-house on the Bowery, to find a place to stay. Only too late does Sheila, and Sid, find out the the stolen diamonds is the last of her problems. Knowing that she's dying Sheila goes to the office of jeweler Arnold Moss, Art Smith, knowing that sleaze-ball of a husband Matt, who ended up beating old man Moss into a bloody pulp, is going to be there to exact vengeance on him.<br /><br />Doucmentry-type drama, based on a true story, with striking black and white on-location photography makes this movie about the horrors of unseen and deadly smallpox unleashed on a unsuspecting public well worth watching.