Take everything out of the closet, wash all the clothing. Wash down all sides of the closet. Purchase some spider sticky traps and put them on the floor along edges of the bedroom and wardrobe walls. They are strips of cardboard with a sticky surface. Spiders walk onto them and are stuck forever. You can probably find the sticky strips at your hardware store.
http://www.bugsaway.com/glueboard.htm

Good luck.

Alice