TORONTO - The author of a bestseller on the controversial Robert Baltovich murder case has been ordered to turn over a vast collection of documents, interviews and tapes that he used to prepare his true-crime book in 1998.

Derek Finkle has been told to hand over material earmarked by the Crown that includes everything from Mr. Baltovich's voluminous prison journals and Christmas cards he sent Mr. Finkle, to correspondence between the writer and film producers interested in securing the rights to his book.

"It makes me a little bit sick to think that the communications which went into my book are going to get used for a completely different purpose -- the prosecution of Rob Baltovich," Mr. Finkle said in an interview. "There is a certain trust that has to be forged between a subject and a writer in something like this."

Mr. Finkle, the editor of Toro magazine, is scheduled to appear in a Toronto courtroom this morning to respond to the Crown subpoena. He said that he intends to fight what he views as a flagrant attempt to turn him into an investigative arm of the state.

The move comes just weeks before Mr. Baltovich's much-delayed retrial is scheduled to commence for the 1990 murder of his girlfriend, University of Toronto student Elizabeth Bain, 22.

He was originally convicted of first-degree murder, but the Ontario Court of Appeal ordered a new trial two years ago.

Mr. Finkle's book, No Claim to Mercy, strongly denounced the Baltovich police investigation and prosecution and strenuously advanced the notion that Mr. Baltovich was wrongly convicted at his first trial.

Mr. Finkle said that homicide detectives began showing up at his workplace in August, asking him to discuss his material and his sources. They did not appear pleased when he insisted on answering their questions in writing, he said.

Besides the effect the subpoena may have on journalists and writers, Mr. Finkle said that some of the tapes in his possession involve interviews with lawyers who agreed to freely criticize Mr. Baltovich's original trial judge after he promised them anonymity.

Mr. Finkle said he is hoping his cases will be championed by advocates for a free press.

"If I had thought when I was writing the book that all this material would be used for this purpose, I probably wouldn't have done it.

"I'm totally prepared to fight, but this is going to wreak havoc on my financial situation. It has cost me at least a couple of thousand dollars already, and we haven't even started to fight yet. I don't work for The Globe or the Ottawa Citizen. I have to decide how much debt I can incur. At a certain point, I may not be able to fight any more."

Mr. Finkle said the attempt to seize his records also underlines the weakness of the Crown's case against Mr. Baltovich. He said the Crown is evidently hoping to find discrepancies in the way Mr. Baltovich described events to investigators and the way he related them to Mr. Finkle.

However, what they won't find is a confession, he said.

"If there was anything incriminating, I would have put it in the book," Mr. Finkle said. "Still, it's a dream scenario for cross-examination. The more material you have, the more there is a chance of finding some sort of contradiction."

He also said that the subpoena fits into a long line of ill-considered acts. "If you are a Crown attorney, this case has received so much attention for all the wrong reasons," he said.

"And now they're subpoenaing a journalist and his material without stopping to think: 'Maybe this isn't such a great idea.' "

Philip Kotanen, one of the prosecutors in the coming Baltovich case, said yesterday there is nothing he can say about the subpoena prior to today's hearing.

When it overturned Mr. Baltovich's conviction last year, the Ontario Court of Appeal criticized the first trial, particularly some of the rulings and comments of the trial judge.