The suspect in what the FBI is calling an “attempted assassination” of former President Donald Trump was a ringleader in a number of cases, an ABC News analysis of his social media profiles has found.

As authorities tried to unravel the motive and details of the case, sources said investigators were looking at whether Routh was frustrated with Trump’s stance on Ukraine. Trump declined to answer when asked whether Ukraine should win its war against Russia during ABC News’ presidential debate last week.

Authorities seized an “AK-47-style” rifle with a scope, two backpacks — one of which contained a ceramic tile — and a GoPro from the scene, Palm Beach County Sheriff Ric Bradshaw said. The potential shooter was between 300 and 500 yards from Trump when he was spotted. The former president was unharmed in the incident, and it’s unclear whether the suspect fired any shots.

Routh’s vehicle was stopped by police after a witness reported his license plate number to authorities. He was taken into custody Sunday afternoon. Authorities expect to file charges in connection with the incident in the coming days, sources told ABC News. The suspect’s motive is not yet known.

Sources say Routh has ties to North Carolina and Hawaii. The FBI is conducting an extensive investigation into Routh’s social media activity, travel and possible criminal records, sources said. Friends, family and acquaintances are also being sought for interviews.

A law enforcement source told ABC News that profiles on X, LinkedIn and Telegram were being investigated for a possible connection to Routh. Routh also appears to have operated a Facebook page, now deleted, that listed the same phone number he shared on his apparent X profile.

When ABC News dialed that number, the following message came on the answering machine: “This is Ryan from Camp Box Buildings in Hawaii, and also from the National Volunteer Center that sends soldiers to Ukraine and Taiwan.”

Online, he appears to have been a prolific promoter of various causes, primarily those involving Ukraine, with numerous posts referencing an effort to recruit soldiers for that country. Specifically, many of Routh’s posts referenced an effort to send Afghan soldiers to Ukraine.

It was not immediately clear whether Routh had actually recruited fighters for Ukraine or whether he had contacts with the Ukrainian military or government.

Routh’s apparent X-profile contained dozens of posts calling on politicians, celebrities and journalists to support Ukraine. In 2022, shortly after Russia’s full-scale invasion, posts to that profile included claims that Routh had traveled to Kiev.

Routh spoke to an ABC News team in the Ukrainian capital of Kiev on April 30, 2022, two months into the war, during a protest by relatives of Azov Battalion soldiers defending the city of Mariupol from Moscow’s troops.

He wore an American flag bandana around his neck and held a handwritten sign that read: “Please world, we need everyone here. This is good versus evil. These children want normal lives…End Russia for our children.”

Routh told The Financial Times that he had tried to join Ukraine’s International Legion for the Defence of Ukraine, which is made up of foreign volunteers, but was rejected because he was too old. Routh claimed the Legion then suggested he recruit other foreigners to serve in the unit.

The International Legion for the Defense of Ukraine told ABC News via email: “We would like to clarify that Ryan Wesley Routh has never been a part of, associated with, or in any capacity connected to the International Legion. Any claims or suggestions to the contrary are completely false.”

A March 2023 post on a LinkedIn profile belonging to Routh included two undated photos of Routh, pictured in front of the U.S. Congress and in Kiev’s Independence Square, respectively. The post was captioned: “In DC and Kiev to provide soldiers for the war effort.”

On June 10, 2020, Routh’s apparent X profile directed a message to X at Trump in which he said he had supported Trump in the 2016 presidential election but that Trump had become a “disappointment.” The message ended with, “I’ll be glad when you’re gone.”

Several X posts in March 2020 indicated support for then-Democratic presidential candidates Sen. Bernie Sanders and Rep. Tulsi Gabbard. Posts in January 2024 indicated support for former Republican presidential candidate Vivek Ramaswamy.

Facebook posts from October and November 2023 promoted conspiracy theories about China, COVID-19 and biological warfare. In December, Routh posted a message on the platform questioning the Jewish people’s historical claim to Israel.

Routh’s phone number was also listed on a website for the so-called “Taiwan Foreign Legion,” which calls for international volunteers to fight for Taiwan in the event of a potential conflict with China.

The most recent post on Routh’s Facebook page also mentions an attempt to convince Taiwan to accept Afghan fighters.

Pierre Thomas, Josh Margolin, Luke Barr, Aaron Katersky, Jack Date, Peter Charalambous, Alexander Mallin, Leah Sarnoff, Joe Simonetti, Helena Skinner and Zohreen Shah of ABC News contributed to this report.