David Wilcock, the American paranormal writer and YouTuber, has died ... TMZ has learned.

Authorities in Boulder County, Colorado say deputies were dispatched Monday after a 911 call came in around 10:44 AM for an unknown problem just outside the town of Nederland.

Authorities say the emergency communications specialist who took the 911 call believed the caller might have been in the middle of a mental health crisis.

Deputies arrived on scene and encountered a man outside a residence who was holding a weapon. Within minutes of their arrival, officials say the man used the weapon on himself. He was pronounced dead at the scene.

Investigators say deputies searched the home and surrounding property and found no one else.

Detectives are now working alongside the Boulder County Coroner's Office to determine the official cause and manner of death.

Wilcock was 53.

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