What are these small bugs in my bed?

For a while now, I have noticed that there are these little bugs occasionally crawling on my bed. I ume that there are much more inside the mattress. They are very small, 2-3mm in length and ovular. They are not very fast moving, slowly making their way across the mattress cover and quilt. Their colouring is predominantly black with yellowish-white mottling on the back. Does anybody have these as well, or know what they are? I tried Google, which revealed nothing except that they don't seem to be bed bugs. If you know what they are, do you have any tips on how to manage/get rid of them? Your help is much appreciated, thank you very much in advance :)