WEST PALM BEACH, Fla. — Federal prosecutors say the man being held in an apparent assassination attempt on former President Trump wrote a letter detailing his plans. In addition, the government says Ryan Routh traveled to Florida a month before his arrest and began casing the golf course and drove by Trump’s Mar-a-Lago estate.

In court papers filed Monday, agents included a letter Routh allegedly wrote and left with an unidentified person in a box along with other possessions. The letter, addressed to “The World” says, “This was an assassination attempt on Donald Trump but I failed you. I tried my best and gave it all the gumption I could muster.”

According to the filing, the person received the box several months earlier but didn’t open it until after seeing news reports of the apparent assassination attempt on Sept. 15. The person read the letter and turned it over to authorities. Prosecutors say the box also contained ammunition, a metal pipe, miscellaneous building materials, tools, four phones, and various other letters.

In the court papers, the government says cell site records for two phones found in Routh’s car show he traveled from the Greensboro, N.C. area to West Palm Beach on August 14. On multiple days over the next month, the government statement says, his cell phones accessed towers near Trump’s golf course in West Pam Beach and his private residence at Mar-a-Lago.

The document, filed ahead of Routh’s detention hearing Monday, contains additional details surrounding his arrest.

On September 15, as Trump was golfing on the fifth hole, the document says a Secret Service agent who was sweeping the area ahead spotted “the partially obscured face of a man in the brush along the fence line.” The agent, also saw a gun barrel protruding through the fence. When it moved, he fired his weapon. Prosecutors say the position occupied by Routh when he was spotted was directly across from the hole on the sixth green.

A witness driving by saw Routh run across the street, get into his vehicle and speed away. The witness made eye contact with Routh and took a photo of his license plate which he immediately shared with law enforcement. Routh was arrested a short time later as he fled north on Interstate-95.

Routh is currently being held on two weapons charges. More charges and an indictment are expected later this week after prosecutors put the case before a federal grand jury.