Hugh Hefner's cause of death has reportedly been revealed.

According to the late Playboy founder's death certificate, which was obtained by both TMZ and the Daily Mail on Tuesday, Hefner died of cardiac arrest, respiratory failure, septicemia and E. coli. Cardiac arrest is listed as the primary cause of death.

SEE ALSO: Hugh Hefner’s widow breaks silence after Playboy founder’s death

It was previously known that Hefner, who passed away last Wednesday at the age of 91, had been suffering from an infection, though it's unconfirmed whether or not that infection was the E. coli that the Los Angeles County Department of Public Health discovered. Sources close to the publisher had also revealed that he came down with a "mild illness" in the weeks before his passing.

See photos of Hugh Hefner throughout his life:



65 PHOTOS Hugh Hefner through the years See Gallery Hugh Hefner through the years LOS ANGELES - JUNE 26,1957: Hugh Hefner with Joan Bradshaw at a Play Boy Party in Los Angeles, California. (Photo by Earl Leaf/Michael Ochs Archives/Getty Images) LOS ANGELES - JUNE 26: Playboy Magazine founder and publisher Hugh Hefner attends a party in his honor with actresses Joan Bradshaw (right) and Susanne Sidney on June 26, 1957 in Los Angeles, California. (Photo by Earl Leaf/Michael Ochs Archives/Getty Images) LOS ANGELES - JUNE 26,1957: Hugh Hefner and guest at a Play Boy Party in Los Angeles, California. (Photo by Earl Leaf/Michael Ochs Archives/Getty Images) LOS ANGELES - JUNE 26,1957: Hugh Hefner with Joan Bradshaw and girls at a Play Boy Party in Los Angeles, California. (Photo by Earl Leaf/Michael Ochs Archives/Getty Images) American pornographer Hugh Hefner and murdered Playboy PLaymate Dorothy Stratten (1960 - 1980), 1980. She holds a plaque naming her 1980 Playmate of the Year. (Photo By Julian Wasser/Online USA Inc./Getty Images) American publisher Hugh Hefner smokes a pipe and holds a pamphlet while balancing a briefcase on his knee, c. 1960. (Photo by Authenticated News/Getty Images) Show Business Illustrated magazine (Original Caption) 1/29/1962 -New York,NY -: Hugh M. Hefner, Editor and Publisher of Playboy, is shown with Cynthia Maddox, the blond cover girl on the February issue of his magazine, arriving by TWA superjet from Chicago. They are here to attend a party given by Ella Fitzgerald at the Basin Street East in honor of winners of the Playboys jazz poll. (Original Caption) Hugh Hefner, publisher of Playboy Magazine, shown as he appeared in court to face charges that nude photograph of Jayne Mansfield in the June issue are obscene. Hefner's attorneys asked for a continuance and his trial was set for July 9 in Municipal Court. 26th June 1966: American millionaire Hugh Hefner, founder of the Playboy empire, during a visit to Britain. (Photo by John Downing/Express/Getty Images) Playboy editor and tycoon Hugh Hefner is greeted by a group of bunny girls from his Playboy Clubs, upon his arrival at London Airport. (Photo by Dove/Getty Images) Heff, is in Britain to officially open his 16th Playboy Club, located in Park Lane, London. (Photo by Sunday People/Mirrorpix/Mirrorpix via Getty Images) Hugh Hefner Boss of the Playboy Empire arrives with an entourage of Bunny Girls at London Heathrow Airport, Saturday 25th June 1966. Heff, is in Britain to officially open his 16th Playboy Club, located in Park Lane, London. (Photo by Sunday People/Mirrorpix/Mirrorpix via Getty Images) Playboy CEO Hugh Hefner with partner model, actress and singer Barbara Benton arrive at Paris Airport. (Photo by James Andanson/Sygma via Getty Images) (GERMANY OUT) Hefner, Hugh *09.04.1926-Verleger (Playboy), USA - mit seiner Freundin Barbara Benton waehrend eines Besuchs in Berlin- 1969 (Photo by Binder/ullstein bild via Getty Images) Portrait taken on August 21, 1970 at Le Bourget airport shows US Playboy Magazine publisher Hugh Hefner and his girlfriend actress Barbara Benton. AFP PHOTO (Photo credit should read STRINGER/AFP/Getty Images) UNSPECIFIED - CIRCA 1970: Photo of Hugh Hefner (Photo by Michael Ochs Archives/Getty Images) UNSPECIFIED - CIRCA 1970: Photo of Hugh Hefner Photo by Michael Ochs Archives/Getty Images Publisher Hugh Hefner and Actress Julie Newmar attend the Rugby Ball on October 20, 1972 in New York City, New York. (Photo by Ron Galella/WireImage) HUGH HEFNER -- Pictured: (l-r) Hefner's girlfriend/Singer, Barbi Benton, unknown, Playboy founder Hugh Hefner discussing promotional artwork for Barbi's 1974 debut album 'Barbi Doll'-- Photo by: Ron Tom/NBCU Photo Bank American publisher Hugh Hefner, of Playboy Enterprises, smiles with his girlfriend, American actor and model Barbi Benton as they attend the 21st annual SHARE fund raiser for The Exceptional Children's Foundation. She wears a feathered blouse and he holds a pipe. (Photo by Frank Edwards/Getty Images) Hugh Hefner and bunnies during 5th Annual International B Bunny of the Year Pageant at The Beverly Hilton Hotel in Beverly Hills, California, United States. (Photo by Ron Galella/WireImage) Hugh Hefner and Sondra Theodore attend Hugh Hefner's Special 25th Anniversary Party on January 10, 1978 at New York New York Disco in New York City. (Photo by Ron Galella/WireImage) Hugh Hefner and Sondra Theodore attend 25th Anniversary Party for Playboy Magazine on January 11, 1979 at Tavern on the Green in New York City. (Photo by Ron Galella/WireImage) NEW YORK, NY - CIRCA 1979: Hugh Hefner and Sondra Theodore circa 1979 in New York City. (Photo by Images Press/IMAGES/Getty Images) 375250 01: Mid-1980's Playboy Mansion. Hugh Hefner and girlfriend Carrie Leigh at the Playboy Mansion. Sondra Theodore and Hugh Hefner (Photo by Ron Galella/WireImage) circa 1980: 'Playboy' magazine founder and publisher Hugh Hefner with 1980 Playboy Playmate of the Year, Canadian model and actor Dorothy Stratten. Stratten wears a strapless top and flowers in her hair. (Photo by Frank Edwards/Fotos International/Getty Images) THE TOMORROW SHOW -- Pictured: (l-r) Playboy founder/publisher Hugh Hefner, journalist/Playboy covergirl Rita Jenrette at the Playboy Mansion -- Photo by: Paul Drinkwater/NBCU Photo Bank Hugh Hefner and Carrie Lee attend the opening party for 'Private Lives' on October 13, 1983 at Madame Wu's Restaurant in Beverly Hills, California. (Photo by Ron Galella/WireImage) Hugh Hefner and playboy bunnies are photographed October 29, 1985 at the re-opening of the Playboy Club in New York City. (Photo by Yvonne Hemsey/Getty Images) Hugh Hefner and Carrie Lee attends the premiere of 'Beverly Hills Cop II' on May 19, 1987 at Mann Chinese Theater in Hollywood, California. (Photo by Ron Galella, Ltd./WireImage) LOS ANGLES, CA - 1989: Playboy Magazine founder and publisher, Hugh Hefner, announces his engagement to Playmate of the Year Kimberly Conrad at a 1989 Los Angeles, California, press conference. Hefner and Conrad divorced in 2003. (Photo by George Rose/Getty Images) 368600 12: Hugh Hefner and friends, Jessica Paisley, left, Mandy Bentley and Sandy Bentley arrive for the 10th Anniversary celebration of the hit television show, 'Baywatch' on May 2, 2000 in Santa Monica, CA. The show has aired nearly 200 episodes since it first premiered in 1990. (Photo by Joe Thomas/Online USA) Kimberly Conrad, Marsden Hefner, and Hugh Hefner during Christie Hefner Hosts Open House Gala for New Headquarters at Playboy Headquarters in Beverly Hills, California, United States. (Photo by Jim Smeal/WireImage) Hugh Hefner and Kimberley Conrad in Photo Booth (Photo by Frank Trapper/Corbis via Getty Images) Nancy Sinatra and Hugh Hefner attend Playboy Magazine Party on April 6, 1995 at the Playboy Mansion in Beverly Hills, California. (Photo by Ron Galella, Ltd./WireImage) The Rembrandts, Yasmin Bleeth, Hugh Hefner & Playboy Bunnies (Photo by SGranitz/WireImage) Hugh Hefner, wife Kimberly and their children during Premiere of 'Star Wars: Special Edition' In 1997 at Westwood in Westwood, CA, United States. (Photo by Magma Agency/WireImage) Playmate Heather Kozar and businessman Hugh Hefner attend Playboy Announces Heather Kozar as the 1999 Playmate of the Year on April 29, 1999 at The Playboy Mansion in Beverly Hills, California. (Photo by Ron Galella, Ltd./WireImage) 7/17/99 Los Angeles, Ca. Hugh Hefner Dancing With Playboy Gals At The Playboy Expo '99 & Playmate Reunion Held At The Pacific Design Center. (Photo By Brad Elterman/Getty Images) 7/16/99 Beverly Hills, CA Hugh Hefner, Shannon Tweed, and Diane Hunter (1954 Playmate) at the First-Ever Playboy Expo. The expo gave a chance for fans to meet centerfolds, celebrities, Bunnies, wirters, artists, photographers, and cartoonists. Photo Brad Elterman/Online USA, Inc. CANNES, FRANCE: Playboy magazine president Hugh Hefner (C) poses with playmates 14 May 1999 on the steps of the Palais des Festivals before the screening of their movie 'Entrapment' in selection for the 52nd Cannes Film Festival. (ELECTRONIC IMAGE) (Photo credit should read PASCAL GUYOT/AFP/Getty Images) BEVERLY HILLS, CA - APRIL 29: Hugh Hefner attends Playmate of the Year Press Conference on April 29, 1999 at the Playboy Mansion in Beverly Hills, California. (Photo by Ron Galella, Ltd./WireImage) Brandi and Hugh Hefner during Madonna's new CD Music Party in Los Angeles, California, United States. (Photo by Jeff Kravitz/FilmMagic, Inc) Madonna, Hugh Hefner & Playboy Bunnies (Photo by Kevin Mazur/WireImage) WEST HOLLYWOOD, CA - DECEMBER 18: Playboy founder Hugh Hefner poses with unidentified model, Shauna Sand (2nd from L) and Holly Madison (R) during Barfly 5th year anniversary party on December 18, 2002 in West Hollywood, California. (Photo by David Klein/Getty Images) Hugh Hefner and Playboy Playmates during Ben Stiller and Christine Taylor Host a Grand Classics Screening of 'Sweet Smell of Success' with YSL at the Playboy Mansion at Playboy Mansion in Beverly Hills, California, United States. (Photo by Donato Sardella/WireImage for Harrison & Shriftman) Hiromi Oshima, Playboy Miss June 2004, Holly Madison, Hugh Hefner, Bridget Marquardt , Kendra Wilkinson, Sara Jean Underwood, Playboy Playmate of the Year 2007 and guest (Photo by Enos Solomon/FilmMagic) Hugh Hefner and models during Hugh Hefner Inducted Into The Erotic Museum's Hall Of Fame at The Erotic Museum in Hollywood, United States. (Photo by Laurence Cottrell/FilmMagic) (EXCLUSIVE, Premium Rates Apply) Carmen Electra and Hugh Hefner *EXCLUSIVE COVERAGE* (Photo by Michael Bezjian/WireImage for Playboy Enterprises) Carmen Electra, top row far left, Hugh Hefner, center, The Girls Next Door and Playmates *EXCLUSIVE COVERAGE* ***Exclusive*** (Photo by Michael Bezjian/WireImage for Playboy Enterprises) Hugh Hefner and girlfriends during The 21st Annual American Cinematheque Award Honoring George Clooney - Arrivals at Beverly Hilton Hotel in Beverly Hills, California, United States. (Photo by Jason Merritt/FilmMagic) LOS ANGELES, CA - DECEMBER 16: Playboy founder Hugh Hefner attends a book signing of 'Mr. Playboy: Hugh Hefner and the American Dream' at Barnes N Noble bookstore on Tuesday December 16, 2008 in Los Angeles, California. (Photo by Byron Gamarro/Getty Images) LAS VEGAS - MAY 15: (L-R) Model Hope Dworaczyk, Playboy founder Hugh Hefner and his girlfriend, December 2009 Playboy Playmate of the Month Crystal Harris, arrive at a party introducing Dworaczyk as the 2010 Playboy Playmate of the Year at the Rain Nightclub inside the Palms Casino Resort May 15, 2010 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images) BEVERLY HILLS, CA - DECEMBER 10: Hugh Hefner and Pamela Anderson attend the Hugh Hefner book signing session at Taschen on December 10, 2009 in Beverly Hills, California. (Photo by Riccardo S. Savi/Getty Images) LOS ANGELES, CA - DECEMBER 09: Playboy founder Hugh Hefner (L) and model Crystal Harris attend an event celebrating the expansion of Griffith Park at Lake Hollywood Park on December 9, 2010 in Los Angeles, California. (Photo by David Livingston/Getty Images) LOS ANGELES, CA - OCTOBER 13: Hugh Hefner attends 'The Rum Diary' Los Angeles Premiere at LACMA on October 13, 2011 in Los Angeles, California. (Photo by Steve Granitz/WireImage) BEVERLY HILLS, CA - SEPTEMBER 19: Playboy Founder Hugh Hefner (C) arrives at the 2011 Ella Awards at The Beverly Hilton hotel on September 19, 2011 in Beverly Hills, California. (Photo by Paul Archuleta/FilmMagic) BEVERLY HILLS, CA - AUGUST 07: (L-R) Hugh Hefner and Crystal Harris attend the Beverly Hills City Council and Playboy Enterprises ribbon-cutting ceremony for Beverly Hills Playboy World Headquarters on August 7, 2012 in Beverly Hills, California. (Photo by Tibrina Hobson/WireImage) HOLLYWOOD, CA - JUNE 15: Publisher Hugh Hefner attends a press conference at the 35th Anniversary Playboy Jazz Festival - Day 1 at the Hollywood Bowl on June 15, 2013 in Hollywood, California. (Photo by Rodrigo Vaz/Getty Images) Los Angeles, CA - OCTOBER 25: Hugh Hefner and Crystal Hefner attend Playboy Mansion's Annual Halloween Bash at The Playboy Mansion on October 25, 2014 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Playboy) LOS ANGELES, CA - JANUARY 16: Hugh Hefner (C) poses with Playboy Bunnies Playmate of the Year 2013 Raquel Pomplun (2nd L) and Miss December 2009 Crystal Hefner (2nd R) at Playboy's 60th Anniversary special event on January 16, 2014 in Los Angeles, California. (Photo by Rachel Murray/Getty Images for Playboy) LOS ANGELES, CA - JANUARY 16: Cooper Hefner (L) and Hugh Hefner pose at Playboy's 60th Anniversary special event on January 16, 2014 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Playboy) LAS VEGAS, NV - FEBRUARY 20: Impersonator George Kane of Florida as Hugh Hefner presents an award during The Reel Awards 2017 at the Golden Nugget Hotel & Casino on February 20, 2017 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Septicemia is an infection that results from the presence of bacteria in the blood and involves severe inflammation of body tissue.

As his health declined, Hefner had shied away from the public eye in recent years, with his last major public appearance coming back in May of 2016 when he helped announce the Playmate of the Year.

Previous reports had indicated that Hefner's health had become "debilitating" as he became bed-ridden, struggled with back problems and was unable to walk without assistance.

Hefner's cause of death comes hours after his wife, Crystal Harris, broke her silence on his death.

"I haven't been able to bring myself to write most people back to thank them for their condolences," the 31-year-old model said in a statement to E! News. "I am heartbroken. I am still in disbelief."

See photos of Crystal Harris with Hugh Hefner:



15 PHOTOS Hugh Hefner and Crystal Harris together See Gallery Hugh Hefner and Crystal Harris together LAS VEGAS - APRIL 04: Crystal Harris and Hugh Hefner attend Hugh Hefner's 83rd birthday dinner at Nine Steakhouse at the Palms Resort & Casino on April 4, 2009 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) LAS VEGAS - MAY 02: 2009 Playmate of the Year Ida Ljungqvist, Hugh Hefner and Crystal Harris attend the Playboy Club at The palms Casino Resort on May 2, 2009 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) HOLLYWOOD - JUNE 13: Playboy founder Hugh Hefner (L) and girlfriend Crystal Harris attend the 31st annual Playboy Jazz Festival at the Hollywood Bowl on June 13, 2009 in Hollywood, California. (Photo by David Livingston/Getty Images) LOS ANGELES, CA - AUGUST 27: Hugh Hefner and Crystal Harris arrive on the red carpet at the Celebrity Catwalk's 9th Annual Fashion Show on August 27, 2009 in Los Angeles, California. (Photo by Heather Holt/Getty Images) LOS ANGELES, CA - NOVEMBER 19: Hugh Hefner and Crystal Harris attend the Los Angeles TASCHEN book launch party at Cross Roads Of The World on November 19, 2009 in Los Angeles, California. (Photo by Michael Caulfield/WireImage) LOS ANGELES, CA - DECEMBER 10: Playboy founder Hugh Hefner and model Crystal Harris attend the Hugh Hefner Autographs Limited Edition Six-Volume Anthology Party by Taschen on December 10, 2009 in Los Angeles, California. (Photo by Michael Bezjian/WireImage) HOLLYWOOD - APRIL 26: Hugh Hefner (L) and Crystal Harris arrive at the 'Iron Man 2' World Premiere at El Capitan Theatre on April 26, 2010 in Hollywood, California. (Photo by Jeff Vespa/WireImage) Playboy owner Hugh Hefner arrives with Playmate and actress Crystal Harris at the world premiere of the restored 'A Star is born' during the opening Night Gala of the 2010 TCM Classic Film Festival in Hollywood, California, on April 23, 2010. AFP PHOTO / GABRIEL BOUYS (Photo credit should read GABRIEL BOUYS/AFP/Getty Images) LAS VEGAS - OCTOBER 21: Hugh Hefner (L) and Crystal Harris attend Crazy Horse Paris at the MGM Resort & Casino on October 21, 2010 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) Hugh Hefner and Crystal Harris attend 20th annual Literary Awards Festival at Beverly Hills Hotel on November 17, 2010 in Beverly Hills, California. (Photo by Brian To/FilmMagic) HOLLYWOOD, CA - APRIL 28: Playboy founder Hugh Hefner (L) and his fiancee Crystal Harris attend the TCM Classic Film Festival Opening Night Gala and World Premiere of the film 'An American In Paris' at Grauman's Chinese Theatre on April 28, 2011 in Hollywood, California. (Photo by Frederick M. Brown/Getty Images) BEVERLY HILLS, CA - APRIL 30: Hugh Hefner and Crystal Harris attend the 55th Anniversary Thalians Gala Honoring Hugh Hefner at The Playboy Mansion on April 30, 2011 in Beverly Hills, California. (Photo by Craig Barritt/WireImage) Hugh Hefner and Crystal Harris attend the opening of 'Playboy Club London' at playboy Club on June 4, 2011 in London, England. BEVERLY HILLS, CA - AUGUST 07: Playboy founder Hugh Hefner (L) and TV personality Crystal Harris attend the Beverly Hills City Council and Playboy Enterprises, Inc.'s celebration of the return of Playboy headquarters to Beverly Hills on August 7, 2012 in Beverly Hills, California. (Photo by David Livingston/Getty Images) HOLMBY HILLS, CA - MAY 09: Crystal Harris (L) and Hugh Hefner attend Playboy's 2013 Playmate Of The Year luncheon honoring Raquel Pomplun at The Playboy Mansion on May 9, 2013 in Holmby Hills, California. (Photo by Charley Gallay/Getty Images for Playboy) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

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