Attorney Carl Douglas, part of the legal team that secured Simpson's 1995 acquittal in the stabbing deaths of his ex-wife, Nicole Brown Simpson, and her friend Ron Goldman, on Friday called the story "ridiculous."
"It's amazing how the world cannot move on from this case!" Douglas said. "And it, and the media, is apparently still fascinated by everything O.J. Simpson."
Another one of his former attorneys, F. Lee Bailey, told Fox 25 News that he thought the story was far-fetched.
"O.J. did not drop [the knife] on his property any more than he did the gloves. The whole thing is ridiculous," he told the station.
The elite Robbery-Homicide Division is investigating a knife now in the possession of the Los Angeles Police Department.
The knife was apparently turned over to a police officer a number of years ago by a construction worker who was helping to raze Simpson's mansion on Rockingham Avenue, police said.
At a press conference at LAPD headquarters Friday morning, Capt. Andy Neiman said the officer was a traffic cop and was working on a movie set when he was given the knife.
Detectives learned of the knife's existence last month, and are now investigating where it came from, according to Neiman, who cautioned that the investigation is still in its early stages.
Neiman told reporters it was unclear why the officer waited nearly two decades to hand over the knife.
"I don’t know why that didn’t happen or if that’s entirely accurate or if this whole story is possibly bogus from the get-go," he said.
Bailey told Fox 25 that he was concerned about the role of the former officer. "A police officer holding it has destroyed any credibility you might prescribe to it," he said.
Alan Dershowitz, who served as an appellate advisor for Simpson's defense, called news of the knife “highly suspect.”
“Where has the knife been? Who has handled it?” Dershowitz asked. “It’s totally suspicious when there is no chain of custody. ... Courts don’t generally allow for that type of thing.”
Dershowitz called the timing of the new information “interesting” because it coincides with a show about the Simpson trial airing on FX.
“You have to ask the question ... 'Why was it revealed now?'" he said. "I think it raises more questions than it answers.”
Dershowitz added: “I think everybody has to take a deep breath and view this with some degree of skepticism.”
Authorities searched for the murder weapon for months after the slayings, and there have been many leads that went cold.
A 15-inch knife with a retractable blade that Simpson purchased at Ross Cutlery in downtown Los Angeles briefly tantalized prosecutors in his criminal trial. They thought it might be the murder weapon, and even asked a coroner to compare that type of blade with the slicing and stabbing wounds of the victims. The fact that no one could locate the knife only added to the intrigue.
But the defense produced the knife -- in an envelope that became known as the "mystery envelope" in the preliminary hearing. Forensic tests later revealed that the knife was in pristine condition, with no scratches or bloodstains to suggest it had been used in the vicious double homicide.
Prosecutors in Simpson's criminal trial never introduced it as evidence.