U.S. investigators are sorting through the social media accounts and other postings of the suspect in the latest apparent assassination attempt of former President Donald Trump, trying to determine a motive and whether anyone else may have been involved.

Sheriff’s deputies in Florida arrested 58-year-old Ryan Wesley Routh, stopping him on a major highway late Sunday after he fled from the former president’s golf course in West Palm Beach, Florida.

Officials said data gathered from Routh’s cellphone showed he lay in wait for 12 hours, hiding in some bushes along a chain link perimeter fence between the course’s fifth and seventh holes.

Routh has been charged with possession of a firearm as a convicted felon and possession of a firearm with an obliterated serial number.

But officials said when investigators with the FBI tried to talk to Routh following his arrest, he invoked his right to an attorney and did not speak.

Instead, the FBI and its partners have focused on obtaining search warrants for a GoPro camera and other electronic devices the suspect is alleged to have left at the scene, as well as for his vehicle and for electronic devices left at the suspect’s previous addresses.

“The subject had an active online presence, and we are going through what he posted and any searches he conducted online,” said FBI Special Agent in Charge Jeffrey Veltri.

“The FBI has sent multiple requests to companies for returns on the subject's phone and social media accounts,” Veltri added, speaking to reporters during a late Monday news conference. “We received several returns and are waiting on additional responses.”

In addition, Veltri said FBI field offices in Honolulu, Hawaii, and Charlotte, North Carolina, have sent agents to interview the suspect’s family members, friends and former co-workers.

Veltri said investigators are also taking a close look at other statements the suspect has made over the years, including interviews he gave to media outlets about trying to recruit Afghan soldiers and others to fight in Ukraine.

The suspect’s online history indicates he, at one point, seemed to support Trump. However, in recent years, his posts appear to suggest he soured on Trump.

In a self-published book, from 2023, Roush appeared to encourage Iran to kill the former president.

“You are free to assassinate Trump,” he wrote in Ukraine’s Unwinnable War, describing the ex-president and current Republican presidential candidate as a “fool” and a “buffoon.”

Yet whether Routh conspired with anyone is not yet clear.

“We do not have information that he's been acting with anyone else at present,” the FBI’s Veltri told reporters.

Investigators are also seeking to answer questions about how the suspect decided to hide and wait in a bush-covered area on the perimeter of Trump’s golf course.

“It was an off-the-record movement, meaning it was not on the on the former president's official schedule,” said Ronald Rowe, acting director of the U.S. Secret Service, the agency responsible for protecting Trump from any and all threats.

“It wasn't a site that was on his schedule. It wasn't part of his schedule,” he said. “So, there was no posting up of it because he wasn't supposed to have gone there in the first place.”

Rowe, though, defended the Secret Service agents guarding the former president, saying the elements put in place “are working” despite having gotten to within 365 to 455 meters of Trump with a loaded AK-style rifle.

The suspect “did not have line of sight to the former president,” Rowe said. “He did not fire or get off any shots.”

“The agents’ hypervigilance and the detail’s swift action was textbook, and I commend them and our partners for an exemplary response,” he added.

Trump praised the work of Secret Service agents as he spoke Monday during an event on the X social media platform, but also added, “We do need more people on my detail.”

U.S. President Joe Biden gave a similar message to reporters at the White House Monday.

"The Secret Service needs more help," Biden said.

"I think the Congress should respond to their needs," Biden said. "I think we may need more personnel."

Rowe, the acting Secret Service director, welcomed the support.

“We have done more with less for decades,” Rowe said, adding that Secret Service personnel are stretched thin.

“We have immediate needs. We have future needs, too,” he said. “So, we're having these conversations, and I feel confident that we will get what we need.”

But in comments to Fox News Digital on Monday, Trump appeared to place some of the blame on President Biden and Democratic presidential candidate Vice President Kamala Harris.

“Their rhetoric is causing me to be shot at, when I am the one who is going to save the country, and they are the ones that are destroying the country — both from the inside and out,” Trump said.

The accused gunman “believed the rhetoric of Biden and Harris, and he acted on it,” Trump added.

During a speech to a conference of historically Black colleges and universities (HBCU) in Philadelphia late Monday, Biden condemned the apparent assassination attempt on his predecessor as un-American.

“In America, we resolve our differences peacefully at the ballot box. Not at the end of a gun,” Biden said.

“America suffered too many times the tragedy of an assassin's bullet,” he added. “It solves nothing and just tears the country apart.”

The apparent attempt on Trump’s life is the second in as many months.

On July 13, a 20-year-old gunman climbed to the roof of a building overlooking a Trump rally in western Pennsylvania and fired multiples times, killing a spectator while wounding the former president and critically injuring two others.

The gunman was then shot and killed by a Secret Service sniper.

The leaders of a congressional bipartisan task force investigating the July 13 assassination attempt on Trump said they have requested a briefing by the Secret Service on Sunday’s incident.

"We are thankful that the former president was not harmed but remain deeply concerned about political violence and condemn it in all of its forms," Congressmen Mike Kelly, a Pennsylvania Republican, and Jason Crow, a Colorado Democrat, said in a statement.

Some material in this report came from The Associated Press.