Cause behind 37-year-old bodybuilder Hayley McNeff’s sudden death revealed

The cause of death has been revealed for bodybuilding champion Hayley McNeff, who passed away unexpectedly at her home in Sudbury, Mass., on Aug. 8 at 37 years old.

The Massachusetts Executive Office of Public Safety and Security confirmed Monday that Hayley McNeff, a former fitness influencer and champion bodybuilder, died from “acute intoxication” due to a fatal mix of heroin, fentanyl, 4-ANPP, cocaine, and norbuprenorphine.

McNeff’s death was ruled an accident, according to the department’s Deputy Director of Communications, Brenna Galvin.

“Hayley was like a beam of light in this world. She had boundless energy and was very determined to achieve whatever she set out to do,” Hayley’s father, Dave, previously told PEOPLE in an exclusive statement.

“She set her sights on bodybuilding and fitness and achieved the highest success that sector offered. She loved us and we love Hayley very much, we miss her madly.”

McNeff attended Concord-Carlisle High School and the University of Massachusetts Amherst, excelling at equestrian, board diving and skiing as she grew up.

She went on to leave a profound impact on the bodybuilding and fitness community in the 2000s, earning state titles in both Maryland and Delaware — and winning the East Coast Classic in 2009.

McNeff was also featured in the 2005 documentary “Raising the Bar,” which examined the lives of competitive bodybuilders.

She would later step away from competition to pursue graduate studies in psychology.

“She had a gift for making those around her laugh and feel welcomed,” McNeff’s official obituary read. “Her energy and determination was a constant in her life and she always accomplished what she set out to achieve. She treasured her friendships and nurtured strong, lasting relationships with those who knew her best. Hayley will be deeply missed by her parents, siblings, extended family, and friends.”

The cause of death has been revealed for bodybuilding champion Hayley McNeff, who passed away unexpectedly at her home in Sudbury, Mass., on Aug. 8 at 37 years old.

The Massachusetts Executive Office of Public Safety and Security confirmed Monday that Hayley McNeff, a former fitness influencer and champion bodybuilder, died from “acute intoxication” due to a fatal mix of heroin, fentanyl, 4-ANPP, cocaine, and norbuprenorphine.

McNeff’s death was ruled an accident, according to the department’s Deputy Director of Communications, Brenna Galvin.

“Hayley was like a beam of light in this world. She had boundless energy and was very determined to achieve whatever she set out to do,” Hayley’s father, Dave, previously told PEOPLE in an exclusive statement.

“She set her sights on bodybuilding and fitness and achieved the highest success that sector offered. She loved us and we love Hayley very much, we miss her madly.”

McNeff attended Concord-Carlisle High School and the University of Massachusetts Amherst, excelling at equestrian, board diving and skiing as she grew up.

She went on to leave a profound impact on the bodybuilding and fitness community in the 2000s, earning state titles in both Maryland and Delaware — and winning the East Coast Classic in 2009.

McNeff was also featured in the 2005 documentary “Raising the Bar,” which examined the lives of competitive bodybuilders.

She would later step away from competition to pursue graduate studies in psychology.

“She had a gift for making those around her laugh and feel welcomed,” McNeff’s official obituary read. “Her energy and determination was a constant in her life and she always accomplished what she set out to achieve. She treasured her friendships and nurtured strong, lasting relationships with those who knew her best. Hayley will be deeply missed by her parents, siblings, extended family, and friends.”