Royals Intruder Armed with Crossbow Arrested at Windsor Castle as Queen Elizabeth Celebrated Christmas Members of the royal family, including Charles and Camilla, joined the Queen for Christmas at the castle on Saturday By Erin Hill Erin Hill Twitter Senior News Editor, PEOPLE People Editorial Guidelines Published on December 27, 2021 10:52 AM Share Tweet Pin Email Queen Elizabeth's 2021 Christmas speech . Photo: Victoria Jones/getty An armed intruder was arrested on the grounds of Windsor Castle on Saturday as Queen Elizabeth and members of the royal family, including Prince Charles and Camilla, Duchess of Cornwall, celebrated Christmas at the castle. Officers responded to a security breach around 8:30 a.m., according to the Thames Valley Police. A 19-year-old man from Southampton was arrested and taken into custody. Officers found a crossbow after searching the man. "We can confirm security processes were triggered within moments of the man entering the grounds and he did not enter any buildings," Thames Valley Police Superintendent Rebecca Mears said in a statement. Queen Elizabeth Delivers Her Most Personal Christmas Speech Ever as She Mourns Prince Philip Members of the royal family were informed of the incident. "We do not believe there is a wider danger to the public," Mears continued. In a statement from London's Metropolitan Police on Sunday, it was revealed that a crossbow was recovered following a search of the intruder." The man was taken into custody and has undergone a mental health assessment — he has since been sectioned under the Mental Health Act and remains in the care of medical professionals," police said. Prince Charles and Camilla, Duchess of Cornwall attend church service at Windsor Castle on Dec. 25. Jonathan Brady/WPA Pool/Getty On Monday, British police said they were investigating a video linked to the 19-year-old man. The video, which was obtained by The Sun, shows a masked individual holding a crossbow and addressing the camera with a distorted voice, saying they wanted to "assassinate" the Queen. According to The Sun, the video was sent from the suspect's Snapchat account the morning of his arrest. Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Like millions of others, the Queen had to rethink her holiday plans and opted to not head to her Sandringham estate in Norfolk, where she normally stays during the holiday season. With the Omicron coronavirus variant causing a huge rise in cases, she decided to stay at Windsor Castle for the second year in a row. Prince Charles and Camilla, Duchess of Cornwall. Jonathan Brady/WPA Pool/Getty Members of the royal family, including Charles and Camilla, joined the Queen for Christmas at the castle on Saturday. Charles and Camilla attended a church service at St. George's Chapel at Windsor Castle on Saturday morning. They were joined by Prince Edward and Sophie, Countess of Wessex and their two children, and the Duke and Duchess of Gloucester. The holiday season is particularly poignant for the Queen this season as it comes just eight months after the death of her beloved husband Prince Philip.