There is wide confusion in the general public, probably thanks to legal drama TV shows about what "hearsay" means and how it applies to a criminal case. Hearsay is an out of court statement made by a party not under oath. Technically, yes, all of the witness statements in a police report are hearsay. But that really doesn't matter because if the witness is important, they are going to be subpoenaed and brought to court and will offer in court testimony that isn't hearsay. The other confusion here is about what constitutes "evidence" in a criminal case. While many cases will have physical and documentary forms of evidence like breath test results, bodycam videos, physical exhibits like a weapon, some cases will not have any of that type of evidence. Instead, the case will be based on witness testimony, which IS a form of evidence and can carry the same weight as scientific or other physical evidence. You can absolutely be convicted of a crime even when the only evidence is witness testimony. This is why it is important to have a defense attorney who is skilled at questioning witnesses.