One of the most important aspects of true Christianity is unity, as stated in God's word, the Bible, at 1 Corinthians 1:10 - "Now I exhort you, brothers, through the name of our Lord Jesus Christ that you should ALL speak in agreement, and that there should not be divisions among you, but that you ALL may be fitly united in the same mind and in the same line of thought." Now let us compare and contrast the numerous individual churches of protestant Christendom with the worldwide church of Jehovah's Witnesses as to whether each of these conform to the scriptural command stated above.
What witness statement, in what case?
yes
On witness's statement to investigators - no. On the usability and admissability of them in court - yes.
A person who gives a statement is called a witness.
Absolutely.
Hearsay
This is hearsay, which is a secondary source of information that is not allowed.
Generally, written testimony is unavailing if the other side does not have a chance to cross-examine the witness. It doesn't hurt to try, though, if that's the best you can do. A notarized statement might be very helpful to establish damages if the other side defaults (does not show up) and you can be awarded whatever damages you can prove.
In some legal systems, the offender may have the right to see the witness statement, but usually personal information is redacted to protect the witness's privacy. The court usually determines what information can be disclosed to the offender.
The most common method of impeaching witness testimony is with a prior inconsistent statement. For example, if a bystander witness watches an accident, she will give a statement to a police officer at the scene. If she told the officer that the traffic light was red, but later testified that the light was green, her statement in the police report could be used to discredit, or impeach, her testimony.
During the "discovery" portion of the trial procedure.
The witness' statement innocently convicted the defendant.