HOUSTON - A Houston woman, who wrote a letter to US President Barack Obama in which she threatened to kill him, was indicted by a federal grand jury, US media reported Wednesday.

Denise O'Neal, 57, was indicted this week, the website of the Houston Chronicle reported. The report did not say the exact date of the indictment.

O'Neal wrote and sent the letter via US Mail on or around November 28 of last year. The letter, described as "long, rambling, and incoherent" was postmarked November 29. She went by the name Teddy Bear Paradise and signed off on the letter as such, the report said.

The Secret Service's Houston Field Office was informed of the letter on December 19 and two agents were assigned to track down the woman at the address on the correspondence, according to court documents.

O'Neal was officially arrested on December 26 and remains in custody now. According to her letter, O'Neal has a long history of mental and physical illness. She could face five years in federal prison and a possible 250,000-dollar fine if convicted.