"I poisoned you," a voice told him on April 17, after he drank some Crystal Light and his tongue began to swell.
"You'll be dead before this investigation takes place," he wrote on May 12. "Why are you writing? We will destroy any evidence that you exist."
The lawsuit, one of five he filed in U.S. District Court against various cities and police agencies in 2012, sheds some light into the mental state of the 39-year-old West Jordan man who police say had "explosive potential" in his backpack when an officer shot the man after a two-hour standoff at the Gallivan TRAX Station platform at 250 S. Main Street on Thursday night.
Mayhew, who represented himself in all the cases, wrote in his lawsuit against the U.S. that he has been hospitalized for mental issues three times, two of which were for "audio hallucinations."
In an email sent to Department of Homeland Security in July that was attached to Mayhew's lawsuit, he writes that law enforcement were attempting to obtain family secrets and confidential information. He said he had heard the "audio transmission" from the implanted BCI device about 14 hours a day for the last year.
Mayhew also wrote in the lawsuit against the U.S. that on two occasions he believed federal agents had come into the home that he shared with his mother.
He wrote that in February, two men sneaked into his walk-in closet.
"The voice from the closet said they were DEA, and then said they were FBI," he wrote in the lawsuit.
West Jordan police investigated, but found no one. As a result of the call, Mayhew said he was committed to a mental health facility.
In two of the federal lawsuits those filed against the state of Utah and the U.S. Mayhew said law enforcement caused his post-traumatic stress disorder as a result of a 1995 arrest in South Salt Lake after he and another man fought with a black man outside a night club and Mayhew was charged with a hate crime.
As a result of the PTSD after his arrest, Mayhew wrote in the lawsuits that he was unable to maintain a job and had to file bankruptcy.
In the South Salt Lake lawsuit, Mayhew wrote that a 2009 arrest for assault and burglary resulted in the loss of two internships he had maintained as a multimedia designer.
He asked for $100 million from the U.S. government, and $2.6 million from the state in a separate lawsuit.
Mayhew requested $180,000 in the South Salt Lake case, which was dismissed Sept. 11.