VACAVILLE, Jan. 19 – A Petaluma woman — arrested by the FBI Monday on suspicion of sending death threats through the mail — carried on what Vacaville prison officials considered a harmless six-month correspondence with Charles Manson at the same time Manson claimed to have sent out a “murder list,” The Reporter has learned.

The first death threat suspected of being from Manson’s correspondent came less than a month after Manson wrote this reporter from his California Medical Facility cell saying he “sent a list of people out to be murdered.”

The threatening letters, Manson’s “murder list” letter, and the correspondence between Manson and the woman all concerned persons Manson considered responsible for cutting trees, CMF and FBI spokesman told The Reporter.

The woman, Patricia Maureen Gillum, also known as Misty Hay, was arrested at her home without incident Monday, San Francisco FBI Special-Agent-in-Charge Charles Bates said. She is being held now in lieu of $50,000 bail, an FBI spokesman reported.

Miss Gillum started corresponding with Manson in June, 1976, shortly after Manson was transferred to Vacaville from Folsom Prison, a CMF official told The Reporter yesterday. They never met, he added.

“Most of their letters to each other were about the environment and how terrible it was that nobody was protecting it,” said Edward George, program administrator of CMF’s Willis Unit, where Manson is imprisoned.

None of the letters between Manson and Miss Gillum contained threats, George said. Miss Gillum, he added, was “very polite” in her letters to prison authorities, and the whole correspondence appeared “harmless.”

The first death threat letter suspected of being sent by Miss Gillum was addressed to the president of the Sierra Club and postmarked in Santa Rosa on Sept. 20, FBI spokesman Frank Perone told The Reporter yesterday. This was less than a month after Manson wrote this reporter claiming to have send out a “murder list” made up of “people who are responsible for the redwood trees being murdered.”

Separate investigations in August by the FBI, the Secret Service and the California Department of Corrections failed to find any evidence that such a “murder list” actually existed, official sources told The Reporter at that time. Manson was never prosecuted in connection with the alleged list, although prison officials said they started reading all his mail more closely after he claimed to have sent it.

The letter to the Sierra Club president read in part: “Charles Manson has ‘fake breakers’ watching you people now…do your part in stopping the cutting down of trees, etc., or else you’ll be chopped up yourselves. For every tree you let be cut down, you shall have one of your limbs cut off! Take heed of this mean letter or die!”

“Fake breakers,” according to Mrs. Gillum, are “people who break their word,” the FBI spokesman told The Reporter.

The letter also told the Sierra Club president to send copies of the book “Clear Cut” to California prisoners Patricia Krenwinkle, Leslie Van Houten, Bruce Davis, Robert Beausoleil, Steven Grogan, and Charles Watson, all once associated with Manson, he reported.

The Sept. 20 letter was signed “Misty,” and a latent fingerprint of Miss Gillum’s was found on the envelope, according to an FBI affidavit filed with the criminal complaint.

The second death threat letter was mailed from San Rafael on Dec. 27 and addressed to Arcata lumber mill owner A.A. Emerson, FBI spokesman Perone said.

“Stop cutting the redwoods NOW,” the Dec. 27 letter said. “Work for a change ( from death to life) or die.”

The second letter was signed simply “M,” and FBI laboratory anaylsis indicated Miss Gillum prepared it, according to the FBI affidavit.

The California Department of Corrections, meanwhile, has decided to leave Manson in CMF’s Willis Unit indefinitely, department spokesman Philip Guthrie told The Reporter yesterday.

Manson’s custody status has been reduced from “maximum” to “close,” allowing him to receive some visitors, George reported. He can, however, be moved quickly back to maximum security at Folsom or San Quentin Prison if the need arises, George told The Reporter.

Manson, now 42, is serving a life sentence following his conviction for masterminding the murders of actress Sharon Tate and six other persons in Los Angeles in 1969.

By GREG deGIERE