Boric acid is what a pro exterminator would use.
Just look for a product called Roach Away. Lowes, Home Depot, Wal-Mart any hardware store should have it in the insectiside area.
Boric Acid is used in hundreds of products. It's used as a fire retardend, treating rotted wood, mold and fungus treatments, ant bait ect.
It kills bug by dehydrating them not poisoning them.