A witness is someone who has firsthand knowledge about a crime or dramatic event through their senses (for example seeing, hearing, smelling, touching), and can help certify important considerations to the crime or event. A witness who has seen the event firsthand is known as an "eye-witness". Witnesses are often called before a court of law to testify in trials. A subpoena commands a person to appear. In many jurisdictions it's compulsory to comply, to take an oath, and tell the truth, under p… (More on Witness)