“and was asked if they could come in. Sure, he said.”
No warrant needed
NEVER EVER give the police or any government agency permission to search your car, your house, your business or your person without having first contacted a lawyer. That should be the first demand “Show me a valid warrant”. Secondly, you should DEMAND that you be able to contact a lawyer. NEVER EVER ALLOW THEM IN YOUR HOME WITHOUT THEM SAYING THEY HAVE A WARRANT OR SUPERCEDING PROBABLE CAUSE OF AN IMMEDIATE NATURE.
NEVER, NEVER, NEVER!!!!!