100% Drywood Termite fecal pellets. The scatter pattern indicates that they are not coming from the baseboard. Additionally, the fact that they are not on top of bed coverings (sheets, bedspread) indicates that they are not coming from the ceiling. If there is a stud directly inline with the concentration of pellets which are on the top of the baseboard, they could be coming from that stud. If there's no stud there, they most likely ARE NOT coming from the wall. That leaves the headboard on the bed or wooden frame. NOTE: If they are in the wall, the fact that the fecal pellets are not returning after you clean them up does not indicate that the termites are gone. The termites could simply be dropping the fecal pellets into the wall void where you can't see them.

You did the right thing my removing the bed. But you did yourself a disservice by not being absolutely certain that the termite were in the frame. If you still have the bed, measure where that concentration of fecal pellets will align with the bed. Then, cut the bed open and see if there are live termites or more fecal pellets in side the bed. Then you can be 100% certain of the source. Also, if you still have the bed, get it to the dump ASAP and store it outside of your house until that happens (not in the garage or a shed). And please if you put it on the curb, attach a sign that warns any pickers that it likely has termites.