Why did the police officers enter John Geddes Lawrence’s apartment without a warrant?

Police officers entered John Geddes Lawrence’s apartment without a warrant because they were responding to a reported weapons disturbance. A neighbor had contacted the police, claiming that a man was "going crazy" with a gun due to a domestic fight or a robbery.1

Upon receiving this report, the officers entered the unlocked apartment with their guns drawn to address the alleged emergency. It is important to note that the lack of a warrant did not become a factor in any of the subsequent litigation regarding the case.1