Natural causes. That's the official explanation for the death of soul icon James Brown in 2006 at the age of 73. Congestive heart failure to be more specific.

Now, however, CNN has come out with a three-part investigation—Part 1, Part 2, and Part 3—raising the bombshell possibility that Brown was murdered.

Writer Thomas Lake interviewed nearly 140 people over two years, including 11 who want a new police investigation. (Two others, Brown's daughter LaRhonda Pettit and son-in-law Darren Lumar, also believed Brown was murdered, but both died before Lake began his story.) One of the 11 is Dr.

Marvin Crawford, who signed Brown's death certificate but now doubts natural causes and suspects an overdose, perhaps accidental, perhaps not, was the culprit. "He changed too fast," Crawford says.

"He was a patient I would never have predicted would have coded. … But he died that night, and I did raise that question: 'What went wrong in that room?'"

Crawford says his recommendation for an autopsy was rejected by the singer's daughter, Yamma, who declined to explain why to Lake.

In addition to Brown's death, the investigation also calls into question the explanation of the 1996 death of Brown's third wife, Adrienne Brown, as an accidental overdose.

The retired police detective on that case gave Lake a notebook from an informant who alleges that a doctor admitted murdering Adrienne Brown with a fatal drug overdose.

As Lake writes, "There is a disturbing pattern of similarities between Adrienne Brown’s death and James Brown’s death 11 years later." Dig in to Part 1 here, in which Lake explains that his investigation began with a call from a circus singer named Jacquelyn Hollander, who not only insists that Brown was murdered but that the singer raped her.

(Suspicions have lingered for years about Brown's death.)

This article originally appeared on Newser: Investigation Raises Questions About James Brown's Death