Prosecutors said that a man accused of trying to kill Trump left a letter outlining his plans.

According to a new document from federal prosecutors, the man who the police claim sat with a rifle in the trees near the West Palm Beach, Florida, golf course earlier this month penned a letter declaring that "this was an assassination attempt on Donald Trump."

Investigators were informed by a witness that many months prior, Ryan Wesley Routh had left a box at his house that "contained various letters, four phones, miscellaneous building materials, tools, and munitions." The petition states that the witness found out about the purported assassination attempt and then opened the box

"This was an attempt to kill Donald Trump, but I failed you," said one letter addressed to "The World." I gave it everything I had—my all and my best effort.”

The letter claims that Trump "ended relations with Iran like a child and now the Middle East has unraveled."