(CNN) -- A Northern California man remained in jail Sunday after he was arrested for threatening the life of U.S. Sen. Barbara Boxer, official said.
Police in San Rafael, California, said they received a report that someone had left death threats in the office voicemail of Boxer, D-California. The messages were left after-hours last week, police said.
The investigation led officers to San Rafael resident Kevin Joseph O'Connell, who was arrested Saturday morning, said police spokeswoman Margo Rohrbacher.
Police did not say how they traced the threats to O'Connell.
The man, charged with one count of making criminal threats, has a first appearance in court slated for noon Tuesday.