Man suspected of apparent Trump assassination attempt wrote letter offering $150k to anyone who could 'finish the job'

• Prosecutors say the man accused in the apparent assassination attempt of Donald Trump previously wrote a letter.
• "This was an assassination attempt on Donald Trump but I am so sorry I failed you," the letter read.
• The letter was found in a box dropped off months prior to the September 15 incident, feds say.

The suspect accused in the apparent assassination attempt of Donald Trump previously wrote a letter confirming his intent to kill the former president, federal prosecutors said in a new court filing on Monday.

Three days after the September 15 incident that unfolded as Trump was golfing at his West Palm Beach, Florida, club, law enforcement was contacted by a civilian who claimed that suspect Ryan Wesley Routh dropped off a box at his home months prior.

That box contained contained a handwritten note that began, "Dear World," according to the court filing.

"This was an assassination attempt on Donald Trump but I am so sorry I failed you. I tried my best and gave it all the gumption I could muster," the letter read, according to the court documents. "It is up to you now to finish the job; and I will offer $150,000 to whomever can complete the job."

The handwritten letter also said that Trump "ended relations with Iran like a child and now the Middle East has unraveled," the court filing says.

According to the prosecutors, the unidentified person who was in possession of the box said that they opened the box only after learning of the apparent assassination attempt on Trump at Trump International Golf Club.

The witness said the box contained ammunition, a metal pipe, miscellaneous building materials, tools, four phones, and various letters, the court filing says.

Routh, 58, has been charged with possession of a firearm by a convicted felon and possession of a firearm with an obliterated serial number. He is scheduled to appear for a detention hearing in Florida federal court on Monday.

Attorneys for Routh did not immediately respond to a request for comment by Business Insider.

A Secret Service agent opened fire on Routh after the agent spotted a rifle poking through the fence of the golf club as Trump was golfing, according to prosecutors.

Trump was at 5th hole when the agent fired at Routh, and Secret Service agents quickly moved the former president from the area after hearing shots fired at the 6th hole.

Routh fled in a car after the Secret Service agent fired the shots but was later taken into custody by law enforcement, according to prosecutors.

In the area where Routh had been hiding, FBI agents found a loaded assault-style rifle with a scope attached. They also found an extended magazine as well as a digital camera, a backpack and a shopping bag hanging from the chain link fence.

Agents also found two license plates and six cellphones, with one containing a Google search of how to travel from Palm Beach County to Mexico, in the car Routh fled in, according to prosecutors.

Agents discovered 12 pairs of gloves, a Hawaii driver's license in Routh's name, a passport, and a handwritten list of dates and venues where Trump had appeared or was expected to be, the court filing says.