O.J. Simpson, acquitted of the 1994 murder of his ex-wife Nicole Brown Simpson and her friend Ron Goldman, may have truly been innocent but covered up for his son, the real murderer.

Private investigator William C. Dear says he’s pieced together the evidence necessary to prove that O.J. Simpson son Jason Simpson was the actual murderer.

Dear, who has written a book on the case titled, “OJ is Innocent and I Can Prove It,” claim’s he found a hunting knife that forensic experts say is the murder weapon. A weapon was never recovered during the police investigation.

While former football great Simpson may be innocent of murder, he is guilty of being an accessory after the fact. Dear claims that he was at the scene of the murder, after his ex-wife and Goldman were dead. He covered up evidence to protect his son and took the rap himself.

The knife, a key piece of evidence, was discovered after Dear claims he dug through Jason Simpson’s garbage and an abandoned storage locker, according to The New York Post.

Jason Simpson also allegedly owned a knit cap like the one found at the crime scene. Dear says he has photos of him wearing it.

The son reportedly had a violent temper. He allegedly assaulted his girlfriend two months before the murders. Jason, who works as a chef, supposedly suffers from “intermittent rage disorder,” according to The Post.

But why murder his step-mother? What motive could he possibly have to commit such a heinous crime? Nicole Brown Simpson was so mutilated, the killer had to be filled with rage.

O.J. Simpson, who was found guilty of the murders in a civil trial, which has a lower standard of proof, is in jail on unrelated theft charges. His son is reportedly working in Florida.