What must be established to ensure the admissibility of a sample obtained at a fire scene? An unbroken chain of custody That the sample was not spoliated The qualifications of the witness presenting the evidence That the sample was collected in accordance with Frank v. Maryland What method would a public fire investigator typically use to legally gain access to a fire scene to conduct an origin and cause investigation where consent is denied by the owner? forcible entry a criminal search warrant An administrative search warrant The exigent circumstance doctrine defined in Michigan v. Tyler