LOS ANGELES - Los Angeles police 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 stabbing deaths of his ex-wife Nicole Brown Simpson and her friend Ron Goldman.

Police Capt. Andy Neiman confirmed the investigation Friday but released few details, stressing that the authenticity of the story is not known.

The weapon used in the killings has been a mystery for decades.

The account of the knife's discovery was first reported by TMZ, which said the knife was found by a construction worker during demolition of the home and given to a police officer who kept it.

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