What is the test for warrantless entry into the home of a suspect?

Law enforcement agents must conform their behavior to the requirements of the Constitution and normally may not enter anyone's property without a properly executed warrant. Absent exigent circumstances (certainly not present here), "the warrantless entry of law enforcement officers into the private home of a suspect, for the purpose of making an arrest supported by probable cause, is barred by the Fourth Amendment...." United States v. Campbell, 581 F.2d 22, 25 (2d Cir.1978) (citations omitted).