Former Los Angeles detective Russell Poole, who accused another cop of involvement in the 1997 murder of rapper Biggie Smalls, died suddenly Wednesday, the Los Angeles County coroner confirmed to Lead Stories. Poole was 60.

Poole, a highly decorated LAPD detective, concluded Smalls was killed in a plot by a corrupt LAPD detective and record exec Suge Knight, but he left the force out of frustration from what his biographer calls "a tangle of politics." Knight is now jailed facing a murder charge in another case.

Poole died while meeting with Los Angeles County sheriff's homicide investigators about the murder of rapper Tupac Shakur, a friend of Poole's told Lead Stories in an email. The Los Angeles Times reported his death was from a suspected heart attack.

Attorney Perry Sanders, who represented Smalls' mother, Voletta Wallace, and his widow, Faith Evans, in a wrongful death suit against the LAPD in the rapper's killing, called Poole "one of America's greatest heroes who never knuckled under to gangster pressure." Sanders praised him as "a kind Eagle Scout with zero ulterior motive."

"The underworld of unsolved crime is dancing a jig, while the family of victims of unsolved crime weep," Sanders said. "Here's to you Russ. You will be remembered with utmost respect by those of us who know your pure heart for as long as we last."

"The main pressure Russell was under was political within the LAPD," said Randall Sullivan, author of the book "LAbyrinth: A Detective Investigates the Murders of Tupac Shakur and Notorious B.I.G., the Implication of Death Row Records' Suge Knight, and the Origins of the Los Angeles Police Scandal."

Production on a movie based on Poole's work is set to start soon, Sullivan told Lead Stories. In fact, he and Poole were set to meet with the director next month. "It's hard to accept that he died right at the brink of the vindication that he deserved and he won't be here to see it," Sullivan said. "I can't make myself grasp that would be so."

Poole was excited about the upcoming film "because it was going to result in the truth coming out," Sullivan said.

Smalls, born Christopher Wallace and also known as Notorious B.I.G., was fatally wounded as he sat in a car at a traffic light after attending a hip-hop event in Los Angeles on March 9, 1997. He was 24. His killing, witnessed by dozens of people, happened six months after the fatal shooting of rival rapper Tupac Shakur in Las Vegas.

Poole, who left the LAPD in 1999, theorized that Knight, who was sitting next to Shakur in a car when he was shot, ordered the killing of Wallace in retaliation for the killing of Shakur, who was signed to his Death Row Records. The homicides of Shakur and Wallace have never been solved and are still officially open.

Poole said in a 2013 interview that he thought he was "just a couple clues away" from solving the case, but "the police departments aren't putting the effort in and they're not listening to people. There are witnesses out there the police never interviewed."

"I don't think the police want to solve it," Sullivan told Lead Stories.

But Poole "was the kind of cop who was incapable of doing anything but his job and he found himself in this tangle of politics," Sullivan said.

He was assigned two politically charged cases to investigate, but what he found was embarrassing for the LAPD, Sullivan said. "All of his superiors and colleagues focused first and foremost on covering their asses."

Besides the Biggie Smalls case, Poole investigated the killing of LAPD officer Kevin Gaines, who was shot to death by fellow LAPD officer Frank Lyga. He eventually discovered that Gaines was connected to Suge Knight and his gangsta rap label Death Row Records, Sullivan said. This led to his revelation that a group of black LAPD officers were allied with Knight and the notorious Bloods street gang. Poole then uncovered evidence that some of these "gangsta cops" could have been involved in the assassinations of Shakur and Smalls, Sullivan said.

"Russell was a plain spoken simple and straight ahead, classic American man who believed that just by doing the right thing and doing your job everything would turn out alright," Sullivan said. "He found himself in a tangle of lies and motives that he could not comprehend because he didn't think that way."

"It's a good day for me because I believe in Karma," former Death Row Records security chief Reggie Wright Jr. said in an interview hours after Poole's death. Wright, who denied he was involved in the Shakur or Smalls shootings, claimed in the interview that Poole was sharing new information with the homicide investigators that he gathered recently from Suge Knight about Shakur's death.

Wright called his ex-boss Knight "a rat" who wanted to trade false information to investigators to help his current murder case, which involves a hit-and-run death near the set of the hit film "Straight Outta Compton."

Lead Stories' Trendolizer is on the story, too, scouring social nets for the hottest trending stories about Biggie, Tupac and the investigations. Scroll down to see the latest.