I N C A S E - I N C A S E O F
After in case we use the Simple Present Tense.
*** Take your raincoat in case it rains. (It may rain so take your raincoat.)
*** I'll take some food with me in case I'm hungry. (I may get hungry, so I'll take some food.)
IN CASE OF
After in case of, we use a noun, gerund or adjective + noun.
*** I’ll use my umbrella in case of rain. (If there is a rain.)
*** Use your gun in case of a robbery. (If there is a robbery, use your gun.)