Illinois v. Gates (1983) is the U.S.Supreme Court decision that established that:

Illinois v. Gates (1983) is the U.S.Supreme Court decision that established that:
 
  a. police officers must provide reliable information when obtaining a search warrant.
  b. police officers must identify the things to be searched.
  c. police officers are allowed to conduct warrantless searches under certain circumstances.
  d. police officers cannot admit evidence into court if they gather evidence using an illegal search warrant.
  e. the flexible totality of circumstances test for determining the existence of the probable cause needed for obtaining a search warrant.