Authorities say a woman accused of threatening to kill First Lady Michelle Obama is in federal custody in Honolulu as the Obama family plans to travel to Hawaii.

The Secret Service says Kristy Lee Roshia called its Boston office last month and told a receptionist, "I will kill Michelle Obama" and "I will kill Marines."

During the same call, she said she would "blow away" Michelle Obama, a Secret Service document states.

Roshia has a history of leaving rambling messages and sending poems, love letters and photographs of herself to the Secret Service, according to an affidavit.

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Agents arrested Roshia on Saturday after she told them she knew where President Barack Obama and his wife will be staying during a visit to the islands later this week.

As early as 2004, she told the agency that "although her mission is to assassinate the president, she has no desire to hurt him."

Roshia was also charged with lunging at a Secret Service agent, striking him in the arms and face during her arrest.

She was being held without bail pending a Wednesday detention hearing.