A paranormal investigator has died suddenly in eerie circumstances, sparking wild online speculation about the involvement of a doll that inspired the horror movie The Conjuring.

Dan Rivera, 54, was touring the US with Annabelle, a supposedly haunted Raggedy Ann doll when tragedy struck.

Emergency services were called to his Gettysburg hotel on Sunday to a report of CPR in progress on a male patient, according to the Evening Sun.

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Annabelle is usually kept at a now closed occult museum in Connecticut where she is locked in a specially built case but was being taken to various sites across the US as part of a popular Devils on the Run tour led by Mr Rivera.

The sold-out Gettysburg leg of the tour was being hosted by the Ghostly Images of Gettysburg Tours at the Soldiers National Orphanage.

The doll was linked to supposed hauntings in the 1970s and was made famous by Ed and Lorraine Warren, a husband-and-wife team of demonologists and paranormal investigators, before gaining further notoriety from The Conjuring film in 2013.

They believed Annabelle was a demonic entity and kept her at their Warren Occult Museum.

Mr Rivera, who was one of the lead organisers of the New England Society for Psychic Research after the deaths of the Warrens who had founded the group, had been promoting taking the doll on tour via TikTok.

Just a day before his death, he told a tour group before showing them into a room where Annabelle was being held that he had taken steps to “protect them” from the doll, including building the case housing using three crosses, representing the holy trinity, and staining it with a finish that contained holy water.

Mr Rivera was also known for his work as a paranormal investigator on the Travel Channel’s Most Haunted Places and was a producer for paranormal television series including Netflix’s 28 Days Haunted.

TikTok has been flooded with videos about Mr Rivera’s death, including some speculating about a possible paranormal cause.

“The Warren’s told you to leave that doll locked up and you did not listen,” one TikToker said.

Another posted a video saying, “I think it is really eerie that Dan’s an army veteran and he passed away in Gettysburg which is believed to be one of the most haunted battlefields in American history, not sure if there is any correlation there but it does give me chills.

A tribute by NESPR posted to Facebook read, “a US Army veteran, Dan served both his country and the people around him”.

“Dan’s passion for the paranormal was rooted in a genuine desire to educate, help and connect with others, whether social media, conventions or investigations with local families seeking understanding and peace.

“Dan’s strong faith was a guiding light in his life. He never wavered in his belief in god and often spoke about the spiritual side of the work we do. We find comfort in knowing that he is now at peace, reunited with loved ones who have gone before him.”

Mr Rivera’s cause of death has not yet been established, although it is not believed to be suspicious.

Final autopsy results are not expected for months.

The NESPR website says Annabelle’s origins date back to when a student nurse was given the Raggedy Ann doll as a gift.

Almost immediately, she and her roommates noticed strange occurrences, with a medium telling them the doll was inhabited by the spirit of a young girl named Annabelle.

“The two roommates tried to accept the doll’s spirit and please it only to have it reciprocate maliciousness and violent intent,” the website reads.

“This is when Ed & Lorraine Warren were called and pronounced the doll demonically possessed. They removed the doll from the house and encased it in a glass box to contain the evil spirited entity.”