According to the ruling in the 1970s tarasoff case, a therapist is required to

A therapist is required to "warn a patient's potential victim/s" according to the ruling in the 1970 Tarasoff case.

They must take responsibility to take reasonable steps to protect a patient's intended victim from danger. When warning, the therapist may include statements made by the patient so as to convey that the threat to the victim is serious.  The therapist is also responsible in transmitting information to other involved healthcare professionals about how dangerous the patient is.