Las Vegas Metropolitan Police in Nevada have confirmed they served a search warrant this week in connection with the unsolved killing of rapper Tupac Shakur.

Detectives carried out the search at a home in Henderson, a suburb of Las Vegas where Shakur was gunned down in September 1996, but did not provide further details of the search, citing the ongoing investigation into Shakur’s murder. Shakur was 25 when he was shot in a drive-by shooting, and no arrests have been made nor suspects currently in custody.

At the time of his fatal shooting, he was in a car with former Death Row Records

CEO Suge Knight when a white Cadillac pulled up beside them and began

shooting out of the back window. Authorities believed the rapper was the intended target of the shooting, but since 1996, the investigation has remained unsolved.