When a defendant files a motion to suppress evidence seized in a warrantless search, what is the burden on the prosecution?

When a defendant files a motion to suppress evidence seized in a warrantless search, "the prosecution bears the burden to prove police conducted the search under a valid exception to the Fourth Amendment's warrant requirement." (People v. Espino (2016) 247 Cal.App.4th 746, 756.) On appeal from the denial of a motion to suppress, we defer to the trial court's express or implied factual findings if supported by substantial evidence, but independently apply constitutional principles to the trial court's factual findings in determining the legality of the search. (People v. Redd (2010) 48 Cal.4th 691, 719.) Here, the underlying facts are not in dispute. Therefore, we need only inquire whether the facts establish exigent circumstances excusing the absence of a warrant.