The message that appeared in Yee's inbox about four weeks ago was much more explicit, Yee said at a press conference Thursday afternoon in his Senate office.
The email warned Yee to stop pursuing gun control legislation; if Yee persisted, the author -- who described himself as a trained sniper -- warned he would assassinate the senator in or around the state Capitol building.
"The threat was unlike any of the other ones I've received in the past," Yee said. "In the past I've received racial slurs, rants about my ethnicity and culture, about China. But instead this was a rather detailed, deliberate and exact set of strategies as to how he would carry out that threat."
Particularly worrisome were the signs of a concrete plan, Yee said. He said his training as a psychologist has taught him that detailed plans are usually a red flag indicating that someone is closer to action.
Yee said he immediately notified his chief of staff, who turned the case over to the Senate sergeants. They passed it on to the California Highway Patrol, and on Tuesday authorities arrested a suspect in Santa Clara County whose apartment contained explosive materials and a firearm. Authorities detonated some bombs they found onsite, Yee said.
The senator has been harassed before, notably when he received a disturbing fax after denouncing radio host Rush Limbaugh. Despite the most recent threat, Yee said he has not requested additional security and would not change his agenda.
"Let me make it very, very clear - I'm going to make it crystal clear - that despite this particular threat and any other threats I am not going to be deterred from addressing the issue of gun violence in this community and this state," Yee said.
PHOTO CREDIT: Sen. Leland Yee, D- San Francisco, speaks to members of the press in his office at the Capitol in Sacramento on Thursday, Feb. 14, 2013. Randall Benton / Sacramento Bee