Court filings have revealed that the man charged with Tupac’s murder, Keefe D, was a “confidential police informant” who tried to implicate hip hop mogul Sean ‘Diddy’ Combs in the rapper’s death. The damning 179-page document, filed by Las Vegas prosecutors, alleges that Keefe worked undercover with LAPD detectives after volunteering information about his role in Tupac’s fatal shooting. The court papers detail how Keefe, known as Duane Davis, became an informant after getting caught “trafficking a large amount of drugs” by the task force. Despite denying involvement in Biggie Smalls’ murder, K…