Lars Nielsen claims that Sidney Rigdon used Parley P. Pratt to collude with Joseph Smith to write the Book of Mormon.
Lars Nielsen, "Religiopithecus Rigdonensis," in How The Book of Mormon Came to Pass (Minnesota: Lars Pauling Nielsen, 2024), 272-273
For months, Rigdon had been desirous to make Smith’s acquaintance and look him straight in the eye, but it would be difficult for him to leave his wife, children, and flock for very long. He entertained the idea of communicating with Smith through correspondence, but the nature of the initial conversation would demand delicacy, nuance, and confidentiality. With the Erie Canal in full operation, he could make the journey to the Palmyra area relatively easily and in just three or four days, but Rigdon preferred to travel on land whenever feasible (possibly due to a phobia that Satan might have special control over water). At the same time, making the journey on foot would take him away from his home and steel chest for much longer than he deemed prudent. And for fear that it might get lost or stolen, he dared not travel with his new scripture on his person, certainly not before he had a chance to make a copy of it. Better for Pratt to meet with Smith first and attempt to discern whether it continued to be consistent with the LORD’s will that Smith come to Ohio. Consequently, in the summer of 1826, Rigdon dispatched Pratt to return to Palmyra and have an audience with Smith. According to his autobiography, Pratt—sporting a full beard and wearing unfamiliar clothes—was both surprised and amused to find that almost no one had recognized him.
Five years later in August 1831, an investigative journalist by the name of James Gordon Bennett spent eight days interviewing the neighbors and acquaintances of the Smith family who still resided in and around Manchester. Six months earlier, Smith and his family had joined up with Rigdon's branch in Kirtland; however, Bennett believed that the key to understanding how The Book of Mormon came to pass was not in Kirtland, but rather much closer to home. For context, the article below was published about six months before the citizens of New Salem (soon to be renamed Conneaut) started affirming that what they had been hearing from The Book of Mormon must have been a plagiarism of "Old Come to Pass." Although I disagree with the tone of the article and the motives that Bennett ascribed to Smith and Rigdon, it does establish that the connection between Rigdon and Smith was facilitated by an unnamed person who had recently been near Painesville, OH. That man, | contend, was Parley P. Pratt.