LOS ANGELES (CBSNewYork/CBSLA.com/AP) — Could the weapon used to kill Nicole Brown Simpson and Ronald Goldman have been sitting right under the noses of investigators all the time?

As CBS2’s Dick Brennan reported, the Los Angeles Police Department will perform forensics tests on the knife that was purportedly found on O.J. Simpson’s former estate. Simpson’s ex-wife and her friend were found stabbed to death at Nicole Brown Simpson’s condo, which was just a short drive from Simpson’s Rockingham estate in Brentwood.

Police sources told CBS News Correspondent Steve Futterman the weapon was a small utility buck knife. That would be inconsistent with what the Los Angeles County Medical Examiner’s office said at the time was a bigger knife used for the murders, CBS news reported.

The knife was given to an officer, the LAPD said.

“The off-duty or retired officer was working in the area of the Rockingham estate and he claimed that an individual, who claimed to be a construction worker, provided him with this knife, claiming that it was found on the property,” said LAPD Capt. Andy Neiman. “So he held onto it until just recently, when we discovered he had it.”

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As CBS2’s Jessica Schneider reported, the lengthy time lapse is leading many to question whether the finding is legitimate, or whether it has any connection to Simpson. Marcia Clark prosecuted the Simpson case, and was urging caution late Friday.

“It might be a hoax,” Clark said. “It might be someone who planted it and who just pretended to find it.”

If, in fact, the knife is the murder weapon — and that is a big if — it would be a major embarrassment to the LAPD and would raise questions about how well the property was searched.

Now-retired LAPD Detective Tom Lange was lead investigator on the Simpson case.

“There were dozens of dozens of hours spent with over 10 officers searching property areas, sewers, streets – a no-stone-unturned type of a situation.”

Investigators said it is believed the LAPD officer was given the knife in the late 1990s, possibly when the Simpson estate was being demolished. Police said he kept it, incredibly, because he believed the case was closed.

Neiman said he was shocked and surprised by the account.

“I would think that an LAPD officer, if this story is accurate as we’re being told, would know that any time you come into contact with evidence that you should and shall submit that to investigators,” Neiman said. “I don’t know what the circumstances are, why that didn’t happen, or if that’s entirely accurate, or if this whole story is possibly bogus from the get-go.”

Last month, the officer told a friend in LAPD’s robbery homicide division about the knife. Supervisors then retrieved the weapon. The traffic officer had been apparently looking to have the knife engraved with the Nicole Brown Simpson case number and framed, according to reports.

“Since then, it’s been in custody and we’re treating it as evidence,” Neiman said. “We are having it tested to see if there is any evidentiary value. This could be just a knife that is totally unrelated to this case. This could be an instance where someone made up a story about the knife.”

According to Neiman, the weapon has been submitted to a lab where it will undergo testing.

“It is being treated as we would all evidence, so it had been submitted to our lab,” Neiman said. “They are going to study it and examine it for all forensic, including serology and DNA and hair samples and that is ongoing as we speak.”

Neiman said the department could consider filing criminal charges against the retired officer, but because he is retired, there will be no administrative investigation at this point.

“Unless you’re a homicide investigator or other investigator, a lot of people don’t realize that those cases remain in the open status,” he said. “I’m not defending what he did, certainly we all would’ve wished he brought [the knife] forward much sooner.”

Simpson was acquitted of the murders in 1995. Under the Fifth Amendment that prohibits double jeopardy, he cannot be tried for the murders again.

The Simpson case is now a TV series, based on the book “The Run of His Life” by Jeffrey Toobin.

“This so-called discovery, if it does in fact have anything to do with the murders, is of great historical interest. But legally, since he has been tried and acquitted, and since there has been a civil judgement against him in the subsequent case by the Goldman family, it just has no legal significance at all,” Toobin said.

In 1997, a jury found Simpson civilly liable for the slayings. He’s now imprisoned in Nevada on a robbery-kidnap conviction.

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