Which organization is tasked with criminal investigations of federal statute violations and domestic intelligence gathering?

The Federal Bureau of Investigation (FBI) is the organization responsible for criminal investigations of federal statute violations and domestic intelligence gathering. Established in the early 20th century, the FBI operates under the jurisdiction of the Department of Justice and plays a crucial role in protecting the United States from various threats, including terrorism, cybercrime, and organized crime.

The FBI not only investigates criminal activities that violate federal laws but also gathers intelligence to prevent and respond to potential threats against national security. This combination of law enforcement and intelligence work allows the FBI to address issues that require a comprehensive approach, blending investigative techniques with intelligence analysis.

In contrast, while other agencies like the Central Intelligence Agency (CIA) focus primarily on international intelligence and operations outside of the U.S., the FBI's mandate includes domestic activities. The Marshals Service specializes in apprehending fugitives and managing prisoners, while the Drug Enforcement Administration (DEA) concentrates on combating drug-related crimes specifically. Thus, the FBI's dual role in investigation and intelligence collection makes it the correct choice for tasks specified in the question.