A judge issued a "bench warrant" for Ack's failure to appear in court. Officer Ick went to Ack's home. As the officer approached the front door, the officer heard a voice say, "Run out the backdoor. The cops are here." Officer Ick forced the front door open, entered and arrested Ack. The officer's entry was ...
1) Unlawful since the officer did not have a search warrant.
2) Lawful because an arrest warrant functions as a search warrant.
3) Lawful since exigent circumstances excused "knock-notice".
4) Unlawful since the officer failed to knock and announce before entering.