Just to share, thru our horrific experience and war with the bed bugs, using HEAT ie hair dryers work best. The result is fast, you see bugs running out from their hiding place. Steamers work too but is bulky, will wet yr mattress and dryers are cheaper. Also, get ready masking tape and glue boards to trap these parasites and do not let it have a chance to run away!
DE food grade works but be v careful in handling as it causes skin irritations and harms our lungs. It is useful to apply a thin coat around the mattress, bed frame and suspected hiding places.
We also place double sided tapes with masking tapes around the beds, floor skirtings to trap the bugs. Also, seal up the gaps in the floor skirtings after putting DE.
I still have some DE left if anyone needs. The battle may be longdrawn and don't give up! It is better to DIY as the pest busters do not guarantee results beyond one month and the bed bugs may return.