Red Stains
Red stains on fabrics, textiles, mattresses, and other bedding items can be a clear sign of bed bugs. Since they feed on blood, these insects might leave behind rusty or red spots when they are smashed. The exact color can be dark when the bugs were killed for a few days or bright red if you have crushed them recently. The shape of these stains might be similar to single blood drops with streaks and smears. Stains can be stubborn and remain even after bedding has been washed. [2]
