LOS ANGELES — Police said Friday they were examining a knife purportedly found at the former home of O.J. Simpson, the one-time football star acquitted of stabbing to death his ex-wife and her friend in the “Trial of the Century” two decades ago.

Forensic investigators were conducting DNA tests on the blade, which was recently turned over to the Los Angeles Police Department by a retired motorcycle officer, Lt. Andrew Neiman told reporters at a news conference.

Neiman said the officer told investigators he was given the knife by a construction worker, who in turn claimed to have found it on Simpson’s property in the Brentwood neighborhood of Los Angeles when the house was being torn down in 1998.

Simpson’s former wife, Nicole Brown Simpson, and her friend Ronald Goldman were stabbed to death on June 12, 1994, at her condominium a few miles away.

The murder weapon had not been recovered at the time of his sensational trial, which was carried live on major television networks in the United States and transfixed much of the nation.

A medical examiner testified for the prosecution at the time that Brown Simpson and Goldman were likely slain with a single-bladed, 6-inch knife.

Police declined to elaborate on the timeline of when the knife was recovered but Neiman said it was possible that “the whole story is bogus from the get-go.”

He also would not name the retired police officer or speculate on why the weapon had been given to police only in the past two months.

“We still don’t know if that is an accurate account of how this item came into our possession,” Neiman said, adding, “If you are the individual that provided that knife (to the police officer) we would love to have you contact our Robbery Homicide Division.”

Authorities have not described the knife but the celebrity website TMZ reported it was a kind of folding knife typically used in hunting and fishing.

NBC News, citing unnamed law enforcement officials, reported that it was a smaller, relatively inexpensive, utility-style blade typically carried by construction workers or other laborers and inconsistent with it being the murder weapon.

Legal experts said Simpson could not be put on trial for the murders again because of the doctrine of double jeopardy.

“There really are no exceptions. Once somebody has been found not guilty of a crime, he cannot be charged with that crime again, under any circumstances,” said University of Southern California law professor Michael Brennan, a former criminal defense attorney. “O.J. could confess to the crimes and he couldn’t be charged again.”

Marcia Clark, the lead prosecutor in the trial, told Entertainment Tonight in an interview she was pleased police were taking the find seriously, even if it was unlikely to lead to new charges.

“The likelihood of any prosecution stemming from this evidence is very, very slim,” she said. “But we have to find out what this means, what the truth of this is.”

Clark also said she believed it was possible that DNA evidence could be lifted from the blade that could shed light on the case.

Simpson was found liable for the deaths of Nicole Brown Simpson and Goldman by a civil court jury in 1997 and ordered to pay $33.5 million in damages to the victims’ families, a judgment that has remained largely unfulfilled.

He was convicted in Las Vegas in 2008 of kidnapping and robbery in a bungled attempt to recover memorabilia from his storied football career and was sentenced to a prison term of up to 33 years.

Highlighting the enduring fascination the case holds for the American public, there were roughly 150 tweets per minute about O.J. Simpson on Friday, according to social media analytics firm Zoomph.

Reports about the knife surfaced just as a popular new FX cable television drama series, “The People v. O.J. Simpson,” chronicling the trial, is airing.