Washington — Federal prosecutors said Monday that they will seek to charge the suspect discovered by the Secret Service with a high-powered rifle in the bushes near former President Donald Trump with attempted assassination of a political figure.

Ryan Wesley Routh, 58, already faces two federal firearms charges stemming from the Sept. 15 incident outside Trump International Golf Club in West Palm Beach, Florida. He appeared in federal court Monday, during which a federal magistrate judge ordered he remained detained until trial.

Routh was denied bond and deemed a flight risk and potential danger to the community. He is represented by a federal public defender, and his attorney's office said Monday morning that she wouldn't be commenting.

Prosecutors said during the hearing that they intend to ask a grand jury to return a new indictment with the additional charge, which carries a maximum sentence of life in prison.

Ahead of the hearing, government lawyers provided more details about the incident in a detention memo calling for Routh to remain behind bars until trial. They revealed that months before the apparent assassination attempt, the suspect left a box with a man that contained ammunition, a metal pipe, building materials, tools, four phones and letters.

One of the letters was addressed "Dear World," and read, "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 memo. The handwritten letter also included a bounty.

Prosecutors said a man, later identified as Routh, and the barrel of a firearm were spotted by a Secret Service agent in the bushes along the fence line at Trump's golf course while he was playing. No shots were fired at Trump, but the agent fired at the suspect, who fled.

Recovered from the scene was an AK-47-style rifle with a scope attached and extended magazine, according to federal law enforcement. The gun was loaded with 11 rounds, and the serial number on the rifle was obliterated, according to the Justice Department's filing. Secret Service agents also found a digital camera, backpack, and reusable shopping bag hanging from the fence, prosecutors said.

According to the Justice Department, the backpack and shopping bag contained plates that "were capable of stopping small arms fire."

A witness near the golf course spotted the suspect running toward a vehicle, and shared with law enforcement a description of the car and license plate. Routh was arrested roughly 50 miles away, and identified as the man seen fleeing from Trump International, federal investigators said.

The FBI then found inside the vehicle, a Black Nissan Xterra, two license plates, six cellphones, 12 pairs of gloves, a Hawaii driver's license in Routh's name, and documents, according to the detention memo. The license plate on the SUV wasn't registered to the car, according to law enforcement.

One of the phones contained a Google search of how to travel from Palm Beach County, Florida, to Mexico.

The incident marked the second in a matter of weeks in which Trump was targeted. A gunman opened fire at the former president's campaign rally in Butler, Pennsylvania, on July 13, killing one attendee and wounding two others. Trump was shot in the ear during the attack.

The FBI and a bipartisan congressional task force are investigating the assassination attempt in Butler, and the scope of lawmakers' probe was expanded to include the latest incident in South Florida.