Why are the most well-publicized cyberattacks frequently investigated by agents with the FBI, the U.S. Secret Service, and the State Department?

because these agencies are the world leaders in investigating and prosecuting cybercrime, which is not recognized as a crime in many European nations

cybercrimes are not investigated by agents from these agencies; cybercrime is solely a local crime and investigated by local police departments

because large-scale cyberattacks frequently originate in other countries and cross state and national borders and are therefore federal crimes

because the United States introduced the Internet to the world and has an obligation to protect the world from misuse