The FBI has abandoned a controversial 18-month investigation into the 1997 murder of the Notorious B.I.G. that focused on whether Los Angeles police officer and Death Row Records founder Marion "Suge" Knight may have plotted the killing, according to a Los Angeles Times report.

The investigation was shut down in January, not long after the FBI discovered that the lead agent on the case, Philip J. Carson, had met with the lawyers for B.I.G.'s mother, Voletta Wallace, and that he'd been subpoenaed to testify in her wrongful-death lawsuit against the city of Los Angeles (see [article id="1489331"]" Notorious B.I.G. Wrongful-Death Suit Can Go To Trial, Judge Rules"[/article]). That case -- which goes to trial on April 12 -- accuses the LAPD of covering up police involvement in B.I.G.'s murder, which took place on March 9, 1997 after a music industry party at the Petersen Automotive Museum.

Carson was ordered not to have any more contact with Wallace's lawyers, who were informed that he would not be testifying in their case, according to the Times report. The bureau expressed concern that Carson may have been unduly influenced by Wallace's attorneys, but denied that he shared any information with them.

Carson's investigation was shut down because it was determined that "there was no basis for prosecution," according to Louis J. Caprino Jr., acting head of the criminal division of the FBI's Los Angeles field office. Caprino denied that the agent's meetings with Wallace's lawyers factored into the decision and said the agent was not found to have acted improperly.

Wallace's lawyer, Perry Sanders, cited an unidentified source in arguing that the LAPD pressured the FBI to shut down the case, a claim the agency denies, according to the Times (see [article id="1485912"]"FBI Joins Investigation Into The Murder Of Notorious B.I.G."[/article]).

The LAPD's investigation into the murder remains open, according to an officer reached Friday (March 11) in the department's homicide division.

Theories on Biggie's killing have ranged from a connection to the East Coast-West Coast beef that also took the life of Tupac, to a 1998 theory pursued by the LAPD that a rogue former cop, David A. Mack, was somehow involved in the murder (see [article id="1425770"]"Ex-Police Officer Suspected In Notorious B.I.G. Shooting"[/article]).

Former LAPD detective Russell Poole's theory that Mack had planned the murder at the request of his friend, Amir Muhammad, sparked the interest of the FBI's Carson after the federal agent saw Poole discuss the case on a 2003 TV special.

Reportedly acting on the suggestions of Wallace family attorneys, Carson contacted Poole and interviewed other detectives and witnesses in the case.

Carson arranged new interviews with Poole and Mack -- who alleges that the FBI agent offered to help reduce his 14-year bank robbery sentence if he cooperated, an allegation the FBI denies -- and conducted surveillance on Muhammad, but the investigation turned up no new evidence, according to the Times.

Check out the feature [article id="1497882"]"Notorious B.I.G.: Still The Illest,"[/article] where Jay-Z, Kanye, Jada, Alicia and others tell us their favorite Biggie verses.