John F. Kennedy

LONDON — Twenty-five minutes before John F. Kennedy was assassinated, a British newspaper received an anonymous tip about "some big news" in the United States, according to the trove of more than 2,800 documents released late Thursday by the National Archives.

The mystery call was made to a senior reporter at the Cambridge News, a paper that serves the East Anglia area of eastern England, on Nov. 22, 1963, at 6:05 p.m. local time. Kennedy was shot shortly afterward, as he rode in a presidential motorcade in Dallas, Texas, at 12:30 a.m. CST. Dallas is six hours behind Britain.