A 54-year-old paranormal investigator died all of a sudden while touring with the supposedly haunted Annabelle doll, his tour organisers told the media.

According to the New York Post, Dan Rivera, a US Army veteran, was in Pennsylvania on his sold-out "Devils on the Run Tour" when the incident took place.

He died on Sunday, shortly after finishing a three-day sellout stop in Gettysburg, which was hosted by "Ghostly Images of Gettysburg Tours" at the Soldiers National Orphanage, the New England Society for Psychic Research (NESPR) said.

According to the Post, Rivera died unexpectedly after completing his tour.

He was touring with the allegedly haunted doll, Annabelle, across the country to various sites.

Firefighters and medics were rushed to his hotel in Gettysburg on Sunday evening following a report of CPR in progress on a male patient.

However, by the time the medics reached the scene, Rivera had died.

The exact cause of the death remains unclear.

According to the Evening Sun, coroner's office personnel said that the death did not appear suspicious, and that Rivera was found alone in his hotel room. A probe is underway.

Notably, Rivera was featured as a paranormal investigator on the Travel Channel's "Most Haunted Places" and served as producer for a number of other shows, including Netflix's "28 Days Haunted."

As part of his tour, he was travelling across US cities with other members of NESPR to show off the allegedly demonic doll.