Is evidence that a witness is afraid to testify or fears retaliation for doing so admissible?

Evidence that a witness is afraid to testify or fears retaliation for doing so is relevant to the credibility of that witness and is admissible. An explanation of the basis for the witness's fear is also relevant on the question of his or her credibility and is well in the discretion of the trial court to admit. There is no requirement to show threats against the witness were personally made by the defendant or the witness's fear of retaliation is directly linked to the defendant. (People v. McKinnon (2011) 52 Cal.4th 610, 668.)