(NewsNation) —A federal judge ordered the man charged in an apparent assassination attempt against former President Donald Trump to stay behind bars while he awaits trial.

Ryan Routh, 58, appeared in federal court on a pair of gun charges, where he was denied bond. Prosecutor Mark Dispoto said the Justice Department will ask a grand jury to bring a more serious attempted assassination charge against Routh.

Authorities say Routh on Sept. 15 pointed a rifle through a tree line at Trump’s West Palm Beach, Florida, golf course where the former president and GOP presidential nominee was playing.

It’s the second apparent attempt on Trump’s life to take place during the 2024 presidential campaign season.

In court documents filed Monday, prosecutors alleged Routh admitted to the scheme in a letter.

“Dear world, this was an assassination attempt on Donald Trump but I am so sorry I failed you,” the letter, addressed to “The World,” reads.

Lawyers representing Routh unsuccessfully sought his release on a $250,000 bond, questioning the prosecution’s evidence. Kristy Militello, a lawyer representing Routh, said the letter indicated “an intent to fail” at the assassination.

However, prosecutors said when Routh was arrested this month, his car contained a handwritten list of dates in August, September and October of places where Trump had appeared or was expected to appear.

What Routh’s letter said

According to prosecutors, Routh put the letter he wrote inside a box and dropped it off at the house of an unnamed witness several months before the alleged assassination attempt. That witness only opened the box, though, after hearing about what happened.

Also inside the box, court documents said, were “ammunition, a metal pipe, miscellaneous building materials, tools, four phones, and various letters.”

A month before his arrest, Routh, the court documents state, traveled from the Greensboro, North Carolina, area to West Palm Beach, Florida.

“On multiple days and times from Aug. 18, 2024 to Sept. 15, 2024, Routh’s cell phone accessed cell towers located near Trump International and the former President’s residence at Mar-a-Lago,” the document says.

What is Ryan Routh charged with?

Routh is charged with possession of a firearm by a convicted felon and possession of a firearm with an obliterated serial number.

A conviction of each charge carries a maximum penalty of 20 years in prison and a $250,000 fine.  

He has not yet entered a plea.

What is Ryan Routh accused of?

Unlike the gunman behind the July 13 assassination attempt in Butler, Pennsylvania, Routh isn’t accused of firing a weapon.

He was about 400-500 yards away from the former president, crouched in bushes near the golf club perimeter and armed with a weapon that had a scope, according to investigators. Trump was not within his line of sight.

The situation began about 1:30 p.m. local time when authorities received a call reporting shots fired at the golf course where Trump was playing. Those shots came from a U.S. Secret Service agent who spotted a rifle sticking through the fence.

A witness told police the suspect fled the scene in a black Nissan, which police located and stopped about 45 miles north of the golf course.

Martin County Sheriff William D. Snyder told WPTV the man “was not armed when we took him out of the car.”

Officials previously alerted about Routh

The Associated Press reported Monday that the FBI, State Department and other U.S. government agencies were given tips about Routh at least four times in the years before the apparent attempt.

One came from an American nurse in Ukraine at the same time as Routh, who said she alerted authorities to his violent tendencies and what she called an obsessive, oddly specific plot to assassinate Russian President Vladimir Putin in his sleep. The nurse was there as an aid worker in the early days of the war in Ukraine, while Routh claimed to be there recruiting foreign soldiers to fight the Russians.

Other tips included one to the FBI in 2019 about Routh being in possession of a firearm after a felony conviction; an online report by an aid worker to the State Department last year questioning Routh’s military recruiting tactics; and Routh’s own interview with Customs and Border Protection about those efforts, prompting a referral for a possible inquiry by Homeland Security Investigations.

Agencies involved either did not respond to requests for comment or said they have no records of these reports, the Associated Press wrote.

NewsNation’s Lauren Powell, The Associated Press and Reuters contributed to this report.