They don’t live in the walls. They live in the mattresses and box springs. But they wander from apartment to apartment. Chances are, if you have them smeone else does, too. They are smart. If they want to get onto a bed and can’t clime, they can climb up a nearby wall and fall onto the bed.
You will have to wash all your clothing and cover your matress in plastic. Do research in yor building to find out if anyone over you or under you has this problem.
It’s not a picknic but,
Good luck.