The suspect in the BTK strangler case (search) was working on a book about his life until authorities found out and cut off contact between him and a woman who was helping him write it.

Kristin Casarona said Thursday that prosecutors have since subpoenaed her notes and letters, as well as photographs and cards Dennis Rader (search) had given her to pass along to his family. She also has been subpoenaed as a witness in the case.

Her name was added to the witness list in Rader's trial last week, and a separate court document filed the same day ordered Rader to have no contact with state witnesses.

Rader, 60, of Park City, is accused of killing 10 people in the Wichita area between 1974 and 1991. BTK stands for "Bind, Torture, Kill." Trial for the former city compliance officer is set to begin Monday.

Casarona said she initially wrote to Rader offering spiritual support. They exchanged letters and she eventually visited him, going to the jailhouse about 10 times beginning in April.

Rader wanted to give his side of the story in the book, Casarona said. She said she and Rader never talked about the crimes he allegedly committed.

"That would be breaking the integrity of the legal system," she said.