WASHINGTON -- Federal agents have detained two further individuals from Missouri and Washington state in connection with an alleged conspiracy to attack President Donald Trump's UFC cage-fighting event at the White House this month.

Officials disrupted the scheme several days ahead of the June 14 White House gathering, court documents indicate.

William Lee Spartacus Falkner of Belfair, Washington, was taken into custody Friday on conspiracy to commit murder charges detailed in documents filed Monday in the Western District of Washington. Jordan W. Rincker, 28, was arrested Sunday and faces the same conspiracy charge in the Western District of Missouri. A court-appointed lawyer for Falkner has not responded to a request for comment, and records do not show an attorney for Rincker. Neither suspect has entered a plea.

"Law enforcement continues to do what it does - move to disrupt and hold accountable those allegedly plotting to do harm on the White House Grounds on June 14," Acting Attorney General Todd Blanche said in a news release.

Authorities learned of the potential threat on June 10, four days before the mixed martial arts event on the South Lawn. The Justice Department had previously announced charges against five people from Ohio, Missouri, Nebraska and California. These latest arrests bring the total facing federal charges to seven.

Officials say group members held fringe conspiracy theories and sought to destabilize the government with the attack.

The investigation began after an Ohio man's mother contacted police over concerns about his recent firearms purchases and online communications, according to an FBI affidavit.

The man, 19-year-old Tycen Proper, told investigators he belonged to a group aiming to spark a revolution by targeting government members. They planned to fly explosive-laden drones into the event and then shoot at fleeing crowd members, the affidavit states. Proper faces firearms charges along with attempted murder of a U.S. officer or employee.

"Mr. Proper appreciates the serious nature of the charges currently pending against him and will address them appropriately in court at the right time," Proper's attorney, Joe Patituce, said Monday. "For now, we are going to move the case forward one step at a time."

Investigators recovered high-powered firearms from several suspects and reviewed encrypted messages among roughly 20 participants who shared maps, aerial photos and discussed a safe house plus escape routes, documents show.

Yet court records leave unclear how close the plotters came to carrying out the plan.

Several questioned suspects or co-conspirators said they intended only to observe rather than commit violence themselves. One planned to attend as a protester but returned home after a vehicle issue. Although they discussed explosive drones, charging documents indicate they were still trying to obtain such equipment when the plot was stopped.

Prosecutors say Rincker gave cash to some members and accepted weapons, a 3D printer, a computer and other items while agreeing to produce drone parts. Rincker told an investigator he wanted the printer only to make and sell crafts, not to build drones, according to an FBI affidavit.

An FBI affidavit states Falkner discussed procuring and operating drones along with tactics and explosives for the plot. After learning the plan had been disrupted, Falkner texted another member that a work trip was canceled because his boss had been arrested and shared a link to an article about the initial arrests, the affidavit shows.

Boone reported from Boise, Idaho.