By By Nick Allen in Los Angeles

The US Secret Service has arrested a woman in Hawaii who is accused of threatening to kill Michelle Obama.  

Kristy Lee Roshia, 35, is said to have called the Boston office of the Secret Service last month, saying "I will kill Michelle Obama" and "I will kill Marines". She is also alleged to have said she planned to "blow away" the first lady.

Agents arrested her in Hawaii after she said she knew specific details of where President Barack Obama and his wife will be staying during a visit there later this week.

 She was detained less than two miles from the home where the Obama family plan to stay.

Roshia has been charged with threatening a family member of the president and assaulting a federal agent after being arrested.

An affidavit filed by the Secret Service in court in Hawaii said Roshia had a history of making rambling telephone calls to the Secret Service office in Boston.

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

On Nov 9 this year a letter was received at the Boston office which included photographs of Roshia and love letters she had written to a non-existent Secret Service agent.

She made her alleged telephone threat to kill the first lady the next day.