Murder Most Foul in Orange County : IF YOU REALLY LOVED ME: A True Story of Murder and Desire, <i> By Ann Rule (Simon & Schuster: $22.95; 492 pp.)</i>

The writer of true crime has an advantage over the writer of crime fiction. He or she has no difficulty with conflicting facts, the illogical progression of plot or outrageous, even unbelievable, testimony as long as the reporting is accurate and objective, and the conclusions consistent with the revealed evidence, because the greatest defense against accusations of unbelievability is the truth.

Ann Rule, a former policewoman with, I presume, some practical experience under her belt and behind her keyboard, has attempted true crime most successfully three times before and now tries it for a fourth with a much-publicized Orange County murder case.

Briefly--and without diluting the suspense in any way--David Arnold Brown, 32, described as “short, not more than five feet seven or so, and thick in the middle, his skin and muscle tone that of a man who rarely went out in the sun and seldom exercised . . . hair dark brown and lank, thinning, and his eyes an oddly variegated mixture of colors . . . scars from teen-age acne (marring) his skin,” has come home to find his wife, Linda Brown, 23, shot to death in their bedroom and a terrified Patricia Bailey, 17, Linda’s sister, holding Linda’s 8-month-old baby, Krystal.

Patricia tells him that Cinnamon Brown, 14, Brown’s daughter by an earlier marriage, had fired a gun at Patti and then gone into Linda’s room and killed her before running from the house. Cinnamon is found hiding in a doghouse wearing a “sweatshirt and sweatpants, both stained now with reddish vomit and urine.” Cinnamon apparently had attempted suicide. Her first words to Fred McLean, Garden Grove homicide investigator, are “Dear God, please forgive me. I didn’t mean to hurt her.”

She is taken to the University of California Medical Center and booked in absentia into the Orange County Juvenile Hall on March 20, 1985. On Aug. 7, her trial as a juvenile begins in Judge Robert Fitzgerald’s Superior Courtroom.

“Even though the very detectives who were gathering evidence and witnesses against Cinnamon Brown all felt ‘hinky’ about the case--nagged by a chill presentiment that they were hunting down a rabbit when a coyote lurked nearby . . . they had virtually nothing tangible that might lead them anywhere but to Cinnamon Brown as the killer,” and so, on Aug. 12, she is adjudged guilty of murder.

The penalty phase begins on Aug. 13. Cinnamon is sentenced to 27 years to life.

So ends “The Crime,” the first part of a four-part book.

Much of that described or surmised in Part One is reprised during the investigation conducted by detectives Fred McLean and Jay Newell, described in depth and detail in Part Two, “The Investigation.”

The detectives discover that Linda had been David Brown’s fifth wife; Brown liked young women before they got “stretch marks”; he had a libido that “approached satyriasis”; he often feigned serious illness in order to manipulate wives, brother, parents and daughter; he had been hospitalized three times for “depression and suicidal thoughts”; he had collected more than $800,000 within six months of Linda’s murder.

But it’s not until a bizarre, manipulative, revealing conversation takes place between David Brown and his daughter, who has been wired in hopes that damning evidence may be revealed, that the work takes fire more than half-way through the book.

All that went before has unfolded with a lack of dramatic power or the accumulation of real menace. Statements such as “People who didn’t obey David’s rules didn’t stay around long,” or an incident describing a chance meeting between Linda and David Brown’s ex-wife, Cinnamon’s mother, Brenda, at the Department of Motor Vehicles about which Brenda remarked, “I wanted to just go over and tell her, ‘Leave him--things are not right,’ ” fail to generate any suspense, or the chill of anticipated horror which the author clearly hopes to achieve.

Of course, it’s not possible in a true-crime story to make things happen that didn’t happen, but the reader is left with the feeling by the end of Part Two that had the material been better organized and orchestrated--in the fashion of fiction--without abusing the circumstances, the book would have elicited more enthusiastic interest.

Part Three, “The Arrest and the Death List,” presents as gripping a plot and as complicated an investigation of a complex character as any imagined in fiction, and Part Four, “The Trial,” wraps up the whole affair with a great deal of energy and skill.

Which brings us full circle:

Writers of fiction and nonfiction alike have the labor of organizing the material at hand to best tell the story. Nonfiction authors have the more difficult task, first because they must strive to give the reader every bit of information possible and second because they are themselves naturally influenced by the painstaking process by which they gathered it. They must find it difficult to throw out some facts or even to avoid the repetition of the same information because different sources gave the same facts a slightly different, and perhaps significant, spin.

But stories, true or false, demand a certain balance, an energetic progress and suspense injected sooner rather than later.

With such a compelling second half, it just seems unfortunate that Ann Rule left it so long getting to the meat and potatoes.