The biggest bombshell of the O.J. Simpson murder trial has been secret for years: According to an insider, three weeks after his acquittal, an ice-cold O.J. stood at his ex-wife Nicole Brown Simpson's grave and brazenly admitted to butchering her and her pal, Ronald Goldman!

The shocking secret confession came just three weeks after The Juice was acquitted of their murders, according to an eyewitness who accompanied him to Ascension Cemetery in Lake Forest, Calif.