O.J. Simpson has been back in the news lately thanks to a couple of television shows revisiting his 1995 murder trial. But a new and somewhat surprising development may keep his name in the headlines for many more days to come.

The LAPD is investigating a knife that was found buried at Simpson's estate, according to a report from TMZ. The knife was alleged to have been found by a construction worker several years ago, at an unspecified time before 1998 when the house was demolished.

So, why are we just hearing about this now?

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TMZ reports that the construction worker handed the knife over to an off-duty police officer, who had decided to keep it for himself. It was only after the now-retired officer contacted a friend at the department to get a file number for the Nicole Brown Simpson/Ronald Goldman murder case -- one he planned to engrave on a frame for the knife he would hang in his home -- that those in charge were made aware of its existence.

This is reportedly a "top-secret" investigation, and the knife is being tested for hair, fingerprints and other biological evidence. Since Simpson was found not guilty in the original trial, he cannot be prosecuted again -- but the police may continue the investigation, as it's still considered to be an open case.