* Star witness in tears on second day of testimony

* Witness says had "intimate" relationship with Petters

* Coleman says she made $19 mln from Petters in 2001-2008

By Todd Melby

ST PAUL, Minn., Nov 3 (Reuters) - The star witness for the prosecution in the fraud trial of accused Ponzi schemer Tom Petters was in tears on Tuesday as she described her decision to confess to the authorities last year.

In her second day on the stand, Deanna Coleman, a long-time associate of Petters and whistle-blower of the estimated $3.65 billion alleged fraud, said she couldn't quit in the summer of 2008 when she was worried the scheme would unravel.

"I was in it too deep, I couldn't," she said in response to questioning from prosecutors.

Coleman said it was then that she went to a lawyer, and eventually decided to go to the FBI. She has pleaded guilty to conspiracy and has been cooperating with investigators, even wearing a wire and recording conversations with her former boss.

It was Coleman's second day on the stand in the Petters trial in front of a federal jury.