A man carrying a gun and a knife was detained Friday by the Secret Service inside State Farm Stadium in Glendale, Arizona, where Charlie Kirk’s memorial event is set to take place Sunday, the agency confirmed to Fox News Digital. Secret Service spokesperson Anthony Guglielmi said the man was detained "in the stadium, but it was prior to the setup of any secure perimeter." The individual allegedly told Secret Service agents that he was at the site to provide private security, The Washington Post also reported, citing a law enforcement official familiar with the matter. A federal source familiar with the investigation told Fox News that the man is a former law enforcement member from another state. LIVE UPDATES: CHARLIE KIRK MEMORIAL IN ARIZONA EXPECTED TO DRAW 100,000, WITH TRUMP AND VANCE HEADLINING "He came and identified himself with expired credentials. They are going through his background and trying to figure out what he was up to there," the federal source added. Guglielmi said to Fox News Digital: "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." "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. The individual is not a member of authorized law enforcement working the event and is currently in custody," Guglielmi added. CHARLIE KIRK'S MEMORIAL: WHAT TO KNOW ABOUT THE EVENT IN ARIZONA The development comes as police are expecting approximately 100,000 people to attend Kirk’s memorial service at State Farm Stadium and an overflow arena on Sunday, Sept. 21, according to media reports. State Farm Stadium has fixed seating for 63,400 and can expand to over 73,000 for larger events, according to the venue. The Department of Homeland Security also designated the memorial service as a "Special Event Assessment Rating Level 1," which is "reserved for events of the highest national significance" and the same severity as the Super Bowl. Erika Kirk, who is Charlie Kirk’s widow, President Donald Trump and Vice President JD Vance are among those set to speak at the event. Fox News Digital’s Alex Nitzberg and Michael Ruiz contributed to this report.