Which agency is leading the investigation into Charlie Kirk's death?

1. Who’s running the investigation — state prosecutors on the legal case, FBI visible in the field

The criminal case against the accused shooter, Tyler Robinson, is being prosecuted in Utah state court with charges including aggravated murder, obstruction and firearm offenses; prosecutors are seeking the death penalty ^{[1] [4]}. At the same time, the FBI played a major, visible role in the investigative work at Utah Valley University and in public communications: the bureau’s director toured the crime scene and addressed the press, and agents executed search warrants and interviewed witnesses and relatives as part of the evidence-gathering effort ^{[2] [3]}.

2. Why both state and federal actors are involved

Local law enforcement and Utah prosecutors handle criminal charging and courtroom prosecution — the vehicle for the aggravated murder and related counts against Robinson ^{[1] [4]}. The FBI’s involvement reflects its role in complex, high-profile crimes that may cross jurisdictions, require forensic resources, or implicate broader security concerns; reporting shows the FBI executed warrants, interviewed family members and its director led public briefings at the scene ^{[3] [2]}.

3. What the public statements reveal — leadership and optics

FBI Director Kash Patel was publicly prominent in the response: he appeared at the Orem crime scene and made news briefings announcing arrests, prompting scrutiny about what the director revealed and how he handled communications ^[2]. Local prosecutors have focused on court filings and courtroom procedure: Tyler Robinson’s first in-person hearing in Provo highlighted prosecutorial charging decisions and the state-level trial pathway ^{[1] [4]}.

4. How reporting frames responsibility for the investigation

News outlets frame the probe as a joint operation: Reuters and The New York Times note the accused is in state custody with Utah charges, while PBS and other outlets describe FBI investigative steps such as search warrants and interviews of relatives ^{[4] [1] [3]}. Coverage emphasizes that criminal charging is a state function while the FBI supplied resources and led parts of the on-the-ground probe ^{[1] [3]}.

5. Points of disagreement and open questions in sources

Sources agree on the dual nature of the response but diverge on emphasis: local-court-centered stories ^{[1] [4]} stress state prosecution and courtroom strategy, while investigative and explanatory pieces ^{[3] [2]} highlight the FBI’s heavy field presence and public role. Available sources do not mention whether the Department of Justice has assumed federal charging authority or whether any federal charges were filed in this case.

6. Political context and scrutiny of investigative leadership

Coverage not only recounts facts of the probe but spotlights political consequences: a leaked report criticized FBI Director Patel’s handling and communications after the killing, with some sources saying he disclosed too much about evidence and was inexperienced for the role — an angle that politicizes the FBI’s involvement ^[2]. That political scrutiny complicates public perception of who “leads” the investigation, even while operational responsibility remains split between state prosecutors and federal investigators ^{[2] [4]}.

7. Bottom line for readers seeking a clear answer

The investigation is being handled jointly: Utah state prosecutors are leading the criminal prosecution of the accused shooter in state court (aggravated murder and related counts), while the FBI led major investigative operations on the ground and publicly announced arrests and developments ^{[1] [4] [3]}. Sources do not report any active federal criminal charges in this matter as of these articles (not found in current reporting).