More than 100,000 mourners assembled at the State Farm Stadium in Glendale, Arizona to attend Charlie Kirk's memorial service.

Security at the funeral was tight as law enforcement personnel worked to prevent a potential emergency from striking. 

Man arrested after falsely claiming to be a police officer

According to Fox News, a man who falsely claimed to be a police officer was taken into custody at the State Farm Stadium on Friday.

"The U.S. Secret Service in coordination with local law enforcement in Glendale, Arizona, is investigating an individual who was observed exhibiting suspicious behavior at State Farm Stadium," Secret Service spokesperson Anthony Guglielmi told Fox News.

"The individual was approached by Secret Service and stated during the encounter that he was a member of law enforcement and that he was armed," Guglielmi continued.

"The individual is not a member of authorized law enforcement working the event and is currently in custody," the Secret Service spokesperson explained.

"The U.S. Secret Service and local law enforcement are investigating the circumstances as to why he was at the location," Guglielmi added.

Suspect was allegedly carrying loaded guns, knives, and false credentials

Fox News later reported that the man was identified as Joshua Runkles, who has been charged with one felony count of impersonating a law enforcement officer.

Runkles, who was allegedly found to be in possession of loaded firearms along with knives and fake law enforcement credentials, is also facing a charge of carrying weapons into a prohibited place.

"The defendant displayed credentials that the issuing law enforcement agency said were invalid," Guglielmi said in a second statement provided to Fox News.

"He had firearms and knives on his person and the Department of Public Safety charged him with criminal impersonation and weapons charges as he did not have the authority in Arizona to have those items," Guglielmi stressed.

Memo warned of "several threats" targeting Kirk's memorial service

Meanwhile, ABC News noted that federal authorities were "tracking several threats of unknown credibility" ahead of Sunday's event.

The network cited a memo which was issued by the FBI, ATF, Secret Service, and the Department of Homeland Security.

"Violent extremists and unaffiliated lone offenders may view the memorial service or related events as attractive attack targets due to the attendance of these individuals, other senior US government officials, state and local government officials, and political activists and due to major international media attention," the document read.