An "accusation" is not evidence, but a person's testimony--what they say happened--IS evidence, and can be enough to charge; it can even be enough to convict, if the person is very persuasive and credible (and the accused is not). So if a person says that you committed a crime and their statement or testimony to that effect is credible, yes, you can be charged. While other evidence (e.g. forensic evidence, photographs, etc.) is very useful and powerful, and a case based only on a person's testimony is weaker, there is no specific legal requirement for forensic or documentary evidence; witness testimony is sufficient. The key thing, the testimony must be based on "personal knowledge"--on what the person him/herself perceived or saw. It's not sufficient evidence if it's just based on something they were told or heard, unless what they were told or heard was essentially a confession by the accused.