Police are reportedly investigating newly uncovered evidence in the O.J. Simpson murder case

New evidence, lost for nearly two decades, has reportedly resurfaced and may shed light on the O.J. Simpson murder case.

TMZ reports that a construction worker found a buried knife in the yard of O.J. Simpson's former estate as long ago as 1998.

The worker reportedly turned the weapon, a folding buck knife, over to a nearby off-duty Los Angeles Police Department officer, who was working as security for a movie shoot across the street. But instead of turning the weapon into police investigators, the officer allegedly brought it home and kept it for years.

In January, the police officer, now retired, reportedly told his friend, an officer in the LAPD's Robbery Home Division, about the knife and his plans to frame it for his wall. He then allegedly asked if the RHD officer could get the departmental record number for the 1994 Nicole Brown Simpson/Ronald Goldman murder case, which he wanted to engrave into the frame.

TMZ's sources said the RHD officer was irate that his friend had kept the knife this long and informed his superiors, who commanded the retired officer to turn in the knife.

Another source with knowledge of the investigation told TMZ that police saw possible blood residue on the evidence, though it's hard to discern due to rust and stains.

An investigation testing the evidence is reportedly being kept top secret.

An LAPD spokeswoman told Business Insider that there's no comment on the report at this time.

O.J. was tried for the murders of Nicole Brown Simpson and Ronald Goldman and found not guilty by a jury in 1995. Since no murderer has been convicted to date, the case remains open. If the reported knife does connect O.J. to the murders, he can't be tried again due to double-jeopardy laws.

In a 1997 civil suit by the victims' families, O.J. was found liable for Nicole and Goldman's deaths in a $33.5 million judgment. Currently, O.J. is serving prison time for armed robbery at a Las Vegas hotel.