Las Vegas: The long-running case into the 1996 killing of rapper Tupac Shakur moved into a courtroom Monday (local time) as witnesses testified on the first day of Duane Keith Davis' murder trial, with prosecutors describing the shooting as 'an act of revenge', and the defence challenging the strength of the evidence after three decades.

Davis, 63, is charged with one count of murder with a deadly weapon in connection with Shakur's death. He has pleaded not guilty, according to CNN.

Prosecutors do not allege that Davis personally fired the shots that killed Shakur. Instead, they contend that he orchestrated the drive-by shooting in retaliation for an assault on his nephew, Orlando Anderson, earlier on the night of September 7, 1996.

The trial began in Las Vegas with opening statements from both sides before the jury heard testimony from four witnesses.

Several members of Shakur's family, including his sister, were present in the courtroom.

Prosecutors described the killing as 'an act of revenge' and argued that Davis had shown 'visceral anger' toward Shakur over the years. They presented surveillance footage, audio clips and witness testimony to establish a timeline of events on September 7, 1996.

Shakur was in Las Vegas to attend a Mike Tyson boxing match when he was fatally shot in a drive-by attack.

The prosecution's case relies in part on Davis' past public statements and admissions concerning the shooting, including audio of him speaking in 2008 about the night of the killing.

Davis' defence focused on the age of the case and what it described as a lack of reliable facts connecting him to Shakur's murder.

Defence attorney Michael Sanft questioned why Davis had not been charged earlier despite his past statements about his alleged role in the killing.

Sanft dismissed those statements and challenged the work of detectives who had previously investigated the case.

The defence also described the work of one former detective as 'biased, sloppy, and incomplete', arguing that the passage of time, corruption and the absence of solid evidence would pose major challenges for prosecutors.

Davis was indicted in 2023 and is the first and only person charged in connection with the rapper's 1996 murder.

Among the witnesses who testified was Garry Dale, a former Las Vegas police officer who recalled pulling over Shakur and Marion "Suge" Knight shortly before the shooting because of a missing licence plate.

As per CNN, Dale also recalled riding in an ambulance with Shakur after the shooting.

According to the testimony provided in court, Shakur responded, "No, we'll take care of it," when asked who had pulled the trigger.

Another witness, Ingrid Stokes, was a passenger in a vehicle travelling near the car carrying Shakur and Knight when the shooting occurred.

She testified about hearing the gunfire and referenced the longstanding culture of silence surrounding street violence with the phrase, "Snitches get stitches."

Retired detective Brent Becker also testified, discussing the historical challenges investigators faced while attempting to solve the case and persuade witnesses to cooperate.

The prosecution's final witness of the day, retired Los Angeles Police Department detective Fred Miller, discussed connections between Davis and another high-profile hip-hop murder investigation involving Christopher Wallace, better known as Biggie Smalls or The Notorious B.I.G.

The opening day brought renewed courtroom attention to one of the most closely watched unsolved killings in hip-hop history. The proceedings are expected to last about a month.

The jury was excused at the end of Monday's proceedings and is expected to return to court at 9 a.m. (local time) Tuesday. The defence is expected to continue challenging the reliability and completeness of the evidence collected over the past 30 years.