Some residents of the Pierre claim that Howard Lutnick, who owns the penthouse, was part of a plot to sell off this symbol of Manhattan glamour and wealth.

The threat, which was made on social media, caused fears of an active shooter on the campus last week, leading to one person being shot and another injured.

The case was the first challenge relating to the treaty, which aims to reduce small-boat crossings of the English Channel by migrants, to reach London’s High Court.