Section 12-1173 - Definition of forcible detainer; substitution of partiesThere is a forcible detainer if:
1. A tenant at will or by sufferance or a tenant from month to month or a lesser period whose tenancy has been terminated retains possession after his tenancy has been terminated or after he receives written demand of possession by the landlord.2. The tenant of a person who has made a forcible entry refuses for five days after written demand to give possession to the person upon whose possession the forcible entry was made.3. A person who has made a forcible entry upon the possession of one who acquired such possession by forcible entry refuses for five days after written demand to give possession to the person upon whose possession the first forcible entry was made.4. A person who has made a forcible entry upon the possession of a tenant for a term refuses to deliver possession to the landlord for five days after written demand, after the term expires. If the term expires while a writ of forcible entry applied for by the tenant is pending, the landlord may, at his own cost and for his own benefit, prosecute it in the name of the tenant.