It's called an eye witness, one of the least reliable forms of evidence.
Yes, absolutely.
Usually, witnesses are issued a subpoena and they come of their own means. If a witness does not want to appear, law enforcement can be directed to bring the witness.
A "warrant' Is a legal document used by law enforcement to to apply to the court for a specific reason (arrest - search - seizure - etc). Witnesses STATEMENTS can be used in the wording of the warrant but a non-law enforcement witness cannot, by themselves, apply for a warrant.
As a citizen, you do not have a duty to act. You may ignore it if you wish, but most would appreciate if you assisted law enforcement.
Yes, police officers have a legal duty to intervene and stop a crime when they witness it happening. This duty is based on their role as law enforcement officers to uphold the law and protect the public.
Stop his boat immediately
I suggest you personally become better acquianted with grammar and the English language.
You can report any suspicious activity or crimes you witness to law enforcement agencies promptly. Providing any relevant information or evidence you may have can also assist them in their investigations.
Tampering with a witness to hinder communication to law enforcement refers to actions taken by an individual to prevent a witness from providing information or testimony to police or other legal authorities. This can include intimidation, bribery, coercion, or any other means to influence the witness's willingness or ability to speak. Such actions are illegal and can result in additional criminal charges, as they obstruct the justice process and undermine the integrity of law enforcement investigations.
Most law enforcement agencies use photography to preserve crime scenes for use in court, both to refresh officers' minds and present visual evidence. Here's the way most police photographers get their start.
Law enforcement was hampered by the widespread corruption of law enforcement officers and other public officials.
It depends on why the witness is not there, what kind of witness it is, what kind of case it is, and what sort of evidence the witness is expected to give. In a criminal trial, the case may be dismissed if there is no witness. Or the trial may be delayed while law enforcement finds and brings the witness to court (if they are ignoring a subpoena). If the witness is ill or travelling, the case may be continued to wait for the witness. If the witness is not key, the parties may proceed without him/her, or they may shift around the order or witnesses to allow that witness to appear later in the trial.