Criminal courts have very specific rules around what kind of evidence can and cannot be admitted at trial. This includes the kind of things that different witnesses can testify about. Your knowledgeable Tampa criminal defense attorney can help you understand how these rules can apply in your situation.
Expert vs. Lay Witnesses
Generally, there are two kinds of witnesses that may testify at trial: lay and expert witnesses. Obviously, expert witnesses are people who have some kind of specialized knowledge or expertise in an area. For example, in an arson case a fire expert may be able to testify as to how fires spread when accelerant is used. Whereas a lay witness is supposed to testify about things that they experienced themselves, rather than things they know. So if someone witnessed the defendant running away from the scene of the crime, they may testify about that but not about anything that requires expertise. If a lay witness testifies about something that requires expertise, the attorney for the other side can object to the testimony.