Over two decades since rapper Tupac Shakur's death, his murder still remains a mystery.

Conspiracy theories have swirled for years about his state of being: from being killed to remaining in hiding.

Regardless, the hip hop prodigy who died too soon has had a lasting effect on culture.

But recently it was discovered in a document by producers from A&E's docuseries Who Killed Tupac? that the gun used to kill Tupac was actually found in a citizen's backyard on 30 May 1998.

The detail came to light after producers found a police document looking into the case.

At first, the .40 caliber Glock was reported to the Compton Police Department, but by 2000, the LA County Sheriff's Department took over jurisdiction and confiscated 3,800 firearms, including that weapon.

In 2006, the officer who was working on the Notorious BIG murder, Deputy T Brennan, was going through records and discovered the document.

He realised the address where the gun was discovered was at the home of a girlfriend of a Crip gangmember who had fallen out with Tupac, according to the new TV series.

It was then that he ordered ballistic testing for the Glock and the results were a match for the weapon that was used to shoot Tupac, A&E producers claim.

Tupac was shot in Las Vegas, so the logical thing to happen would have been for the gun to be turned over to the Las Vegas Police Department (LVPD).

But the weapon was never turned over to the LVPD, where his murder remained unsolved; a federal prosecutor on the case recommended that the gun not be turned over in case it would alert "potential conspirators".

One theory is that returning the weapon could have triggered fresh gang violence if in fact there was a murder tied back to the Crips.

When A&E contacted the LVPD some officers weren't sure if the gun was ever received while others definitively said it didn't get to them.