The “based on a true story” film genre is often a worst-of-both-worlds purgatory that mixes fact and drama to the point that both are weakened. “City of Lies” (2021), a dormant film about the even-more-dormant murders of rap icons Notorious B.I.G. and Tupac Shakur, would have been better either as a documentary or as a completely fictionalized police procedural with “names changed to protect the innocent,” as they used to say on the old LAPD television shows. Conspiracy theories surrounding the unsolved murders have reduced Biggie and Tupac to abstracts, like Amelia Earhart. This film clouds the narrative even further.