I Did Not Make It Up.

December 8, 1980, during a game between the Miami Dolphins and the New England Patriots, Cosell stunned millions by announcing the murder of John Lennon during Monday Night Football. There were 3 seconds left in the game. The Patriots were lining up to kick a field goal – the game on the line – when Gifford said into the open mic, “I don’t care what’s on the line, Howard, you have got to say what we know in the booth.”
Cosell then announced:

“Yes, we have to say it. Remember, this is just a football game, no matter who wins or loses. An unspeakable tragedy confirmed to us by ABC News in New York City: John Lennon, outside of his apartment building on the West Side of New York City, the most famous, perhaps, of all of The Beatles, shot twice in the back, rushed to Roosevelt Hospital: Dead On Arrival. Hard to go back to the game after that news flash, which in duty bound, we have to take.”