Putting clothes and bedding in the dryer on high heat is the method to kill bed bugs. You can pick up a bedbug on public transportation or anyplace that has seating that has a cushion like a restaurant. Library or theater. They can live for about 6 months without a meal. They usually hide during the day, crawling in Wall outlets out the crease of bedding and mattress. You can call your local housing inspector if you see them to get the landlord to treat for them. If they wait to long they may have to heat treat the whole building. Chances are a neighbor or visitor brought them into the building from someplace else. Look for them laying eggs up at the ceiling corners and putting clothing in covered plastic bins helps keep clothes safe. The diatomaceous earth helps also, but don't let the baby near it.