It was February 27, 1977. Working on some kind of tip, cops busted into Keith Richards room at the Harbour Castle Hilton (now the Westin) and found Keef in possession of a quantity of drugs. It was the beginning of a bad, bad period for him.
There’s now a book on the episode: Jason Schneider’s Before They Make Me Run: Keith Richards and the Bust That Saved The Rolling Stones. It’s the first comprehensive look at what happened and the aftermath of the whole shebang.