<P> The Secret Service's primary investigative mission is to protect the payment and financial systems of the United States from a wide range of financial and electronic - based crimes including counterfeit U.S. currency, bank & financial institution fraud, illicit financing operations, cybercrime, identity theft, intellectual property crimes, and any other violations that may affect the United States economy and financial systems . The agency's key focus is on large, high - dollar economic impact cases involving organized criminal groups . Financial criminals include embezzling bank employees, armed robbers at automatic teller machines, heroin traffickers, and criminal organizations that commit bank fraud on a global scale . </P> <P> The USSS plays a leading role in facilitating relationships between other law enforcement entities, the private sector, and academia . The Service maintains the Electronic Crimes Task Forces, which focus on identifying and locating international cyber criminals connected to cyber intrusions, bank fraud, data breaches, and other computer - related crimes . Additionally, the Secret Service runs the National Computer Forensics Institute (NCFI), which provides law enforcement officers, prosecutors, and judges with cyber training and information to combat cybercrime . </P> <P> Protection of the nation's highest elected leaders and other government officials remains the other key mission of the United States Secret Service . After the 1901 assassination of President William McKinley, Congress also directed the Secret Service to protect the President of the United States . </P> <P> The Secret Service is authorized by law to protect: </P>

When did the secret service start guarding the president