Notorious B.I.G., 1995.

Notorious B.I.G. in Brooklyn. 

Clarence Davis/NY Daily News Archive via Getty Images

Former Los Angeles Police Department detective Russell Poole, who led investigations on Notorious B.I.G.'s murder, has died. 

Investigation Into The Death Of Notorious B.I.G. Continues

Poole died suddenly on Wednesday of a possible heart attack while speaking with Los Angeles County Sheriff's homicide investigators about a cold case, Los Angeles Times reports. 

Poole was a leading investigator on the killing of Notorious B.I.G. (born Christopher Wallace) death in 1997 when the rapper was slain leaving a Soul Train Music Awards after-party at the Petersen Automotive Museum in Los Angeles. After months of investigation, Poole accused a corrupt LAPD officer of conspiring with Death Row Records head Suge Knight to pull off the murder.

The murder was retaliation for the killing of Tupac Shakur in Las Vegas six months prior, Poole believed. 

Notorious B.I.G. Family Attorney Criticizes LAPD After Autopsy Report

Following, then police chief Bernard C. Parks ordered Poole to cease his investigation. In protest, Poole retired from the department in 1999. 

"I think I was getting too close to the truth," Poole told CNN in 2011. "I think they feared the truth would be a scandal."

Poole would go on to file a lawsuit against the LAPD for violating his First Amendment rights when the department attempted to prevent him from going public with his information from the investigation. And later worked as a private investigator, in part, continuing his work to solve the case.