Find the source of bed bugs by looking for signs of the bugs, such as stains and spots, or by looking for them in places where they usually hide. Further, the source of bed bugs can sometimes be located by understanding their behavior and habit patterns.
In terms of looking for physical signs of the bed bugs, any rusty or red-colored stains on the bed sheets or mattress can be indicative of an infestation. When bed bugs are crushed, the reddish color is what is usually left behind. Alternatively, a dark spot on the bed can be indicative of the excrement of the bed bugs. The excrement stain left behind by the bugs is similar to the look of how a marker would bleed on fabric. Further, any minuscule eggs or eggshells, or obviously any live bed bugs, could pinpoint the source area.
While bed bugs typically like to hide in places where piping is and in the cracks of the headboard or frame of the bed, in heavy infestations, they have been known to also favor the seams of couches and chairs, loose wallpaper and electrical appliances. Keep in mind as well that bed bugs have no problem traveling five to 20 feet from established hiding places to feed.