Lady Elizabeth Montgomerie at Lainshaw Castle

Wikipedia's article on the murder gives the ghost as a single sentence and does not name a witness. It says Lady Elizabeth was reported to have fled to Ireland, but in fact stayed close by, and that she was eventually allowed to return to her husband and never left the grounds of Lainshaw again for the rest of her life. The murder is well documented, and was followed by a wave of revenge killings across Cunninghame. Whether the ghost is linked to the signal is not stated in the source and should not be assumed.