Which agency typically investigates serious crimes such as homicide at a federal level?

The Federal Bureau of Investigation (FBI) is the agency primarily responsible for investigating serious crimes at the federal level, including homicides. Established to address federal law enforcement issues, the FBI has specialized units and resources to handle complex and high-profile cases that cross state lines or involve violations of federal laws.

The FBI often collaborates with other law enforcement agencies, providing assistance that may include technical support, forensic analysis, and investigative resources that local and state agencies might not possess. This collaboration is essential in dealing with serious crimes that may have broader implications, affecting multiple jurisdictions or involving federal statutes.

In contrast, the other agencies mentioned focus primarily on local or state law enforcement and may have jurisdiction limitations that prevent them from engaging in federal investigations. Therefore, the FBI's role is crucial for serious crimes that demand a federal response.