The report revealed that injuries cause by a single bullet killed the rapper, whose real name was Christopher Wallace, during a drive-by shooting in March 1997. Wallace was hit by four bullets after leaving a music industry event, but one that hit his heart, left lung and colon caused his death, the 23-page report states.
Perry Sanders Jr. said he was not given any notice that the report would be released, and he criticized police for not closing one of Los Angeles' highest-profile unsolved murders, especially since he had been told that police had identified those responsible.
"I've been advised by the homicide detective that was in charge of the investigation and is no longer with the department that the crime has been solved for several years now," Sanders told The Associated Press. "This was confirmed by at least one other person who is currently on the force, and it is ridiculous that an arrest has not been made for a crime that's allegedly been solved for several years."
Both Los Angeles police and the FBI investigated Wallace's killing, which came just months after another rap superstar, Tupac Shakur, was gunned down in Las Vegas. The FBI looked into whether any Los Angeles police officers were involved in Wallace's shooting.
The deaths of Wallace and Shakur have been the subject of rampant speculation about the motives. The one-time friends became rivals and instigators in an East Coast-West Coast rap rivalry during the mid-1990s.
A 2011 book by former Los Angeles police detective Greg Kading claimed both murders had been solved, although no arrests have been made and federal prosecutors in 2005 declined to file charges after a lengthy, bi-coastal investigation. Wallace is from the New York City borough of Brooklyn.
Police spokesman Richard French declined to comment, saying Wallace's killing remained an open investigation.
The coroner's report had been sealed for more than 15 years until police lifted a hold on it last week, Chief Coroner Investigator Craig Harvey said. The report details the trajectory of each of the shots that hit the rapper and states there were no signs of alcohol or drugs in his system when he died.
Sanders, who dropped a federal civil lawsuit against the city in 2010 in order to give investigators an opportunity to investigate further, said solving the case was more important than any lawsuit.
"In no way shape or form is this about civil litigation," he said. "This is about the criminal justice system and it functioning properly."
The lawsuit Sanders filed on behalf of Wallace's family and widow Faith Evans ended in a mistrial in 2005 after attorneys discovered the city withheld a trove of LAPD documents.
The civil case could be refiled, although that has not yet occurred.
In March 2011, the FBI electronically released files on its investigation, which were heavily redacted but shed new light on the efforts that investigators took to try to find those responsible for the rapper's death. Agents conducted surveillance and interviews in Los Angeles, San Diego and New York, the files showed.
The FBI referred all questions on the case to Los Angeles police.