We now know Playboy founder Hugh Hefner’s official causes of death

FILE - In this April 7, 2006 file photo, Playboy founder Hugh Hefner poses at the Playboy Mansion in the Holmby Hills area of Los Angeles. The new book "Playboy Swings" releasing on Sept. 14, 2015, details Hefner's contribution to popularizing jazz and his stand against racial segregation in entertainment. (AP Photo/Kevork Djansezian, File)

Playboy mogul Hugh Hefner died of cardiac arrest and respiratory failure after contracting septicemia, an infection caused by e. coli that is resistant to drugs, according to The Blast.

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Hefner died on Sept. 27 in his home surrounded by his wife, Crystal Harris, and his four children. He was 91 years old.

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The media mogul was in poor health in the last six months of his life and a long-term back condition that limited his mobility, his ex-girlfriend Barbi Benton told PEOPLE.

Hefner was buried next to his first-ever centerfold, Marilyn Monroe, on Saturday at Westwood Village Memorial Park in Los Angeles in a private service from family.

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