(AP) - Detectives are investigating a knife purportedly found some time ago at the former home of O.J. Simpson, who was acquitted of murder charges in the 1994 stabbings of his ex-wife Nicole Brown Simpson and her friend Ron Goldman, a police spokesman said Friday.



A citizen supposedly found the knife, possibly during demolition of Simpson's former home years ago, and turned it over to a now-retired police motorcycle officer who was working as a security guard at a filming location, police Capt. Andy Neiman said.



The knife was being analyzed by an LAPD crime lab for DNA or other material.



It came to light in the past month, but Neiman did not say how that occurred, stressing the authenticity of the story was not confirmed.



Investigators were looking into whether "this whole story is possibly bogus from the get-go," he said.



The weapon used in the killings has been a mystery for decades. Other knives have surfaced during the case but were not linked to the crimes.



In 1994, a salesman testified at a preliminary hearing that he sold Simpson a knife before the killings.



That same month a woman turned in a red-stained kitchen knife she said she found near Simpson's home, and a handle and a piece of blade of a knife were found in a tank that collects waste from airplanes at O'Hare International Airport in Chicago, where Simpson flew the night of the killings.



In 1998, a residential construction crew found a folding-blade knife in Simpson's former neighborhood but police said there was no evidence to show it was related to any crime.



Neiman said investigators didn't know the identity of the person who handed over the recently discovered knife and asked him or her to come forward.



The killings occurred June 12, 1994, and led to the "Trial of the Century" in which the former football star was acquitted by a jury that deliberated only four hours.



In 1997, a civil court jury found Simpson liable for the slayings and awarded millions of dollars in damages to the victims' families.



Neiman did not believe that Simpson could be charged again with murder if the latest knife is linked to the killings.



"I'm not an attorney, but it's my understanding from being a police officer for nearly 30 years that double jeopardy would be in place here," he said.



Loyola Law School professor Laurie Levenson, a former federal prosecutor who is a longtime observer of the Simpson case, agreed.



"If they were going to find this knife and make it useful in the murder trial they should have found it 20 years ago, and they didn't," she said. "It will just raise more questions about the incompetence of the investigation and probably lead to more books and more movies."



The department was looking into whether criminal charges could be filed against the ex-officer who held onto the knife. An officer who comes into contact with evidence is required to turn it over to investigators, Neiman said.



Internal administrative charges were unlikely since the officer is now retired.



Simpson is imprisoned in Nevada for a 2008 armed robbery and kidnapping conviction.



The account of the knife's discovery was first reported by TMZ.