An Illinois Probable Cause Affidavit is a sworn statement by a law enforcement officer, prosecutor, or other authorized person that sets forth the facts and circumstances that constitute probable cause for an arrest, search and/or seizure. The affidavit must be based on the officer's personal knowledge, observation, or belief. There are two types of Illinois Probable Cause Affidavit: the Arrest Warrant Affidavit and the Search Warrant Affidavit. The Arrest Warrant Affidavit is a statement from a law enforcement officer or prosecutor that presents the facts and circumstances to support the need for an arrest warrant. The Search Warrant Affidavit is a statement from a law enforcement officer or prosecutor that presents the facts and circumstances to support the need for a search warrant. Both affidavits must provide sufficient evidence to a court to establish probable cause that a crime has been committed and that the person named in the warrant is likely involved in the crime.