Police are investigating a video linked to a man who was found with a crossbow at Windsor Castle on Christmas Day.
The footage, obtained by The Sun newspaper, appears to show a masked person in a hoodie holding a crossbow.
They are shown addressing the camera saying they wanted to "assassinate the Queen" in a "revenge" mission.
Scotland Yard confirmed detectives were "assessing the contents of a video" following the arrest of a 19-year-old man from Southampton.
The police spokesman declined to comment on the identity of the person in the video.
Buckingham Palace has also declined to comment.
A 19-year-old suspect was sectioned under the Mental Health Act after being found in the castle grounds.
[Source: BBC]
