Have you ever heard of a murder investigation where the police focus on a certain suspect and collect evidence with an eye toward nabbing that suspect, while ignoring other evidence that would lead them to someone else? Unfortunately, this kind of thing happens all too often, and in many cases, it results in the wrong man being arrested for the crime. In such a case, the investigation is not being conducted properly. Police shouldn't gather evidence for suspect A - they should simply gather evidence. And when all the evidence has been collected, a process of reasoning typically leads to the conclusion of what scenario is most likely to have occurred that would result in the evidence that we now observe. That scenario includes the manner of death (was it a murder or something else?) and the course of events that led to the death, including the people involved and what actions they took.
This is the true nature of evidence. It is simply a set of observable facts about some state of affairs. The evidence tells a story, but only after using a process of reasoning from the facts to a conclusion. Evidence, in and of itself, could lead to one conclusion or another, depending on the reasoning used. Good reasoning can lead to conclusion A, which is correct. Bad reasoning can lead to conclusion B, which is false. In both cases, the evidence is the same. In other words, evidence is not evidence for A or for B, it is just evidence. It is the process of reasoning that makes us say something is "evidence for B", but that reasoning could be wrong.