With a digital camera, black plastic bag of food, and loaded SKS-style rifle, Ryan Routh arrived at Donald Trump's Palm Beach golf course and waited for almost 12 hours.
Court documents have provided details of the allegations against the 58-year-old after the second apparent assassination attempt against the former president.
Mr Routh made a brief federal court appearance in Florida on Monday, local time, where he faced two gun charges.
The initial criminal counts will allow authorities to keep Mr Routh in custody as the investigation continues.
And experts say more serious charges are likely to be laid.
This is what we learned from Mr Routh's first court appearance, documents provided to the court, and what could happen next.
The charges
The Federal Bureau of Investigations (FBI) has said former president Trump was the target of "what appears to be an attempted assassination" at his golf club in West Palm Beach on Sunday.
A Secret Service agent fired at Mr Routh when he was spotted in the bushes with a rifle as Trump played golf a few hundred metres away.
The suspect allegedly fled the scene but was arrested about 40 minutes later driving north on Interstate 95.
Shackled and wearing a blue jumpsuit, Mr Routh briefly appeared in court on Monday where he faced two federal weapons charges:
- Possession of a firearm by a prohibited person — convicted felon
- Possession of a firearm with an obliterated serial number
Dr Harry Melkonian, a practising lawyer and honorary associate at the United States Studies Centre, said the charges were significant.
The first count alleges that Mr Routh illegally possessed his gun in spite of multiple felony convictions, including two charges of possessing stolen goods in 2002 in North Carolina.
The other charge alleges that the serial number was "obliterated and unreadable to the naked eye", in violation of federal law.
"The charges are quite substantial and carry heavy penalties," Dr Melkonian said.
"The first carries a penalty of up to 15 years in prison, it's not a minor charge."
He could face five years in prison if convicted on the second charge.
The Initial investigation
Dave Aronberg, the state attorney for Palm Beach County, told American news outlet MSNBC that attempted assassination charges could be considered even if the accused had not fired a shot.
So far, there has been no evidence that Mr Routh fired his gun and the Secret Service said he "did not have a line of sight to the former president".
The incident comes just two months after another armed man was able to take aim at Trump, grazing his ear with a bullet during a July 13 rally in Butler, Pennsylvania.
Dr Melkonian said at this stage of the investigation, charging Mr Routh with weapons-related crimes would be a lot easier than trying to prove he intended to shoot the Republican presidential candidate.
"In order to justify the arrest, they (investigators) had to show to the judge some basic probable cause for the arrest, and that's what this was all about," he said.
"From a prosecution standpoint, charging someone who is not qualified to have a gun with possessing a gun is a lot easier than trying to prove that someone intended to shoot Donald Trump."
According to a "probable cause" criminal complaint filed by FBI special agent Mark Thomas, mobile phone data indicates that Mr Routh "was located in the vicinity of the area of the tree line" at the Trump International Golf Course from just before 2am Sunday until about 1:30pm.
A Secret Service agent had been walking the perimeter of the golf course when he spotted what appeared to be a rifle poking out of the tree at 1:31pm and the agent opened fire.
Mr Routh could have therefore been camped out at the scene for nearly 12 hours before he was noticed.
During their investigations, law enforcement officials allege they discovered a publicly viewable Facebook post from about July 10 from Mr Routh, directing his followers to contact him on a WhatsApp number.
Authorities were able to confirm the number belonged to Mr Routh, and contacted T-Mobile to provide mobile phone usage data that placed him at the golf course on Sunday.
Mr Routh allegedly fled the area after coming under fire from the agent, getting in a Nissan sport utility vehicle and driving off "at a rate of high speed".
Court documents say he left behind:
- A digital camera
- Two bags, including a backpack
- A loaded SKS-style rifle, 7.62x39 calibre rifle with a scope
- A black plastic bag containing food
The serial number on the SKS-style "was unreadable to the naked eye," Mr Thomas wrote.
He added that from his "training and experience" he was aware that SKS-style, 7.62x39 calibre rifles, were not manufactured in the state of Florida.
"Therefore, I submit that there is probable cause that to believe that the SKS-style rifle, which was seized from the tree line at Trump International, have previously travelled in interstate or foreign commerce," he stated.
Mr Routh was convicted in North Carolina of multiple felony counts of possession of stolen goods, according to the criminal complaint.
This included a felony for possession of a weapon of mass destruction in 2002.
What happens next?
Magistrate Judge Ryon McCabe concluded there was probable cause to charge Mr Routh with possession of a firearm by a convicted felon and possession and receipt of a firearm with an obliterated serial number.
A detention hearing has been scheduled for September 23.
Charges in a federal criminal complaint are preliminary, and typically need a grand jury indictment before the case can proceed.
Dr Melkonian said prosecutors often used that time to add additional counts, and the grand jury "tends to do what the prosecutor ask".
He added that the state of Florida may also lay charges.
At a federal level, threatening the life of a former president only carried a maximum penalty of five years' imprisonment, Dr Melkonian said.
"The assassination statutes, which include attempted assassinations, don't apply to someone who isn't president," he said.
"But if there's going to be a state of Florida prosecution, I suspect they won't do anything until the federal case is over."
