Bed Bugs Black Markings.
This is a small view of a portion of the piping of a mattress.
In the depression along the piping, you see, roughly 10+ , adult and baby bed bugs.
Generally speaking, the Black Markings caused by the fluid like Feces are the most prominent tell tale sign that there is a Bed Bug presence!
On non absorbent surfaces, these appear as dots, just like ink would. And on absorbent fibres of a mattress fabric material, this excrements fluid bursts into the fibres, just like ink would.
The Red Spots are produced when a Bed Bug is inadvertently crushed by the movement of a host, typically a human, and typically tossing and turning in bed. In this photo such a spot is not obviously present.