The tragedy in Tucson was an eye-opener for the entire nation. Among those killed, Federal Judge John Roll.
Deputy US Marshal Jon Lemay is in charge of a unit called Protective Intelligence in Boston. They are responsible for evaluating threats against Federal Judges, the US Attorney, all federal prosecutors and all of their staffs.
The unit's workload is heavy. In 2009 there were more than 2,000 inappropriate communications that needed to be investigated, according to Lemay.
People are allowed to voice their displeasures with judicial rulings and sentencings, but when the communications cross the line they are looked into.
The first step in the investigation often involves a visit to the sender's home, where they ask about their intentions.
Oftentimes the sender's show mental illness and might be ruled incompetent to stand charges. The Marshals hope changes can be made in order to prevent future tragedies.
Arizona shooter Jared Loughner contacted Congresswoman Gabrielle Giffords but never contacted Judge Roll.