The thriller dramatizes "one of the most notorious and unsolved cases in recent time."
Depp plays LAPD detective Russell Poole, the real life officer who investigated the death of the rapper -- born Christopher Wallace -- who was killed in a 1997 drive-by shooting shortly after Tupac Shakur's murder. The movie sees him teaming up with reporter "Jack" Jackson (Whitaker), a character clearly inspired by Randall Sullivan, who wrote the book "LAbyrinth" on which the movie is based.
"A murder like that only goes unsolved if the police don't want to solve it," Depp's Poole says in the trailer, while warning that if a connection between cops and the murder was ever unearthed, "it would ruin the city."
Here's the official synopsis for the movie, hitting theaters September 7:
Based on the true story of one of the most notorious and unsolved cases in recent time, CITY OF LIES is a provocative thriller revealing a never-before-seen look at the infamous murder of The Notorious B.I.G. shortly following the death of Tupac. L.A.P.D. detective Russell Poole (Johnny Depp) has spent years trying to solve his biggest case, but after two decades, the investigation remains open. "Jack" Jackson (Forest Whitaker), a reporter desperate to save his reputation and career, is determined to find out why. In search of the truth, the two team up and unravel a growing web of institutional corruption and lies. Relentless in their hunt, these two determined men threaten to uncover the conspiracy and crack the foundation of the L.A.P.D. and an entire city.
If the story sounds familiar, that's likely because USA's "Unsolved: The Murders of Tupac and the Notorious B.I.G" recently dug into it as well, with "Westworld" star Jimmi Simpson playing Poole on the series.