Greenleaf's fourth outing for lawyer-turned-shamus Marsh Tanner, Fatal Obsession (1983), was taut, credible, a marked improvement over his earlier, implausibly contrived efforts. And The Ditto List (1985), a non-mystery novel, demonstrated Greenleaf's strong talent for grittily comic realism. So this new Tanner case--overlong, overwritten, luridly convoluted--is a surprising, disappointing regression. Dianne Renzel Usser, 41, co-founder of the Berkeley Community Crisis Center, is found mutilated and bloodily murdered in her bedroom. Was she killed by her arrogant husband Lawrence, a Berkeley Law School professor and compulsive philanderer? So the police believe. But somber, 45-ish Tanner, hired by the dead woman's parents to investigate, soon uncovers a dank tangle of perhaps-related subplots: the behavior of the Ussers' teen daughter Lisa, a druggy punk-runaway who's been consorting with a homicidal psycho called ""The Maniac""; the disappearance of Lisa's even wilder girlfriend Sherry (whose body will eventually, gruesomely, surface); Usser's law-school feuds, his amoral liaisons, his obsessive interest (abetted by a creepy psychiatrist) in championing the insanity-plea in murder cases. And, after trailing crazy Usa through an assortment of kinkily cultish (and by now hackneyed) milieus, Tanner arrives at the cumbersome solution--which involves two killers, lots of psychosis, and one epically unconvincing murder-motive. Again, Greenleaf's basic talents--for ironically hard-boiled narration, for edgy California dialogue--provide solid, overall readability here. But nearly every chapter is marred by overkill--intrusively artsy metaphors, pretentious clumps of introspection, excessively stagey portraits (especially in the punk/drugs/sex scenes)--while the insanity-plea material, intriguingly substantial at first, is never really developed. All in all: a distasteful, unpersuasive plot-stew, sporadically flecked with atmosphere (Berkeley '80's/'60's nostalgia) and characters.