Not the least of the pleasures to be gleaned from "Murder in Texas," the two-part NBC movie airing tomorrow and Monday at 9 p.m. on Channel 4, is heralding the return of Farrah Fawcett, who comes out from under the hair dryer and away from the remains of some truly awful theatrical features like "Sunburn," and proves she can act.

No one will be able to say she is just another billowy hairdo again. In fact, for "Murder," her fair is pulled back in a palomino ponytail, and Fawcett gives a touching, poignant performance that ends halfway through the film, when the Texas socialite wife she plays dies miserably and mysteriously in a lonely hospital room.

The film is based on the case of Dr. John Hill, the ambitious Texas plastic surgeon indicted in 1970 for the murder of his wife but never convicted of the crime. He himself was allegedly shot to death by a burglar in 1972. The father of Hill's first wife, oil millionaire Ash Robinson, was later cleared of charges that he had conspired to have his son-in-law murdered.

Fawcett plays the first-wife, Katharine Ross the second, Andy Griffith -- looking a little like Harry Truman and registering like a Titan missile -- plays the father, and Sam Elliott, minus his usual four- or five-pound mustache, plays Hill, who by all or most accounts was, whether a wife killer or not, a man with a psychopathic dedication to the shrine of his own existence.

It may be that people won't take an extremely beautiful woman seriously on the screen until she lets herself look awful. Fawcett deftly captures the pathos of the neglected wife who busies herself with horse shows and other distractions and keeps trying to pretend her marriage can be patched up again.

Then when she gets terribly ill after eating a French pastry forced on her by her husband (who been warned by the father-in-law that a divorce would be economically ruinous for him), Fawcett gets the chance to go through the wringer. "I think everything's gonna be all right," she says gamely, only a day or two before dying.

There has been more than one account of the crime and its incredible, Byzantine history. Tommy Thompson's "Blood and Money" is the best known book, but David Merrick scooped that one up; the status of it as a film project is in doubt. Producer Dick Clark, meanwhile, had bought the rights to "Prescription Murder" by Ann Kurth, who married Hill after the first wife died. Murder in Texas" is based on that book and, the credits say, other sources.

The single nagging problem with the film is its attempt to be both a docudrama and a thriller. Producer-director Billy Hale handles the thriller elements very well -- oh very, very well -- but because it aspires to some sort of authenticity, the screenplay by John McGreevey has to concede that the case was never fully solved, that tantalizing questions remain. The picture ends with the suggestion that Hill might be alive; viewers may feel more teased than satisfied.

However, along the way, the film is diabolically, hauntingly, even elegantly suspenseful. McGreevey's script is exceedingly shrewd in meting out details and building accumulative tension, and Hale keeps coming up with intelligent or at least persuasive surprises. Clark hardly stinted on production; Leonard Rosenman, long a top-flight Hollywood composer, wrote the immaculately portentous score, and the cinematography of Donald M. Morgan is exceptional for television (a shorter version of "Murder" will be released theatrically abroad).

The film opens in Houston, 1968, where a dream marriage between Joan Robinson Hill of the horsey set and Dr. John Hill, the ambitious plastic surgeon, is coming to and end, accelerated by the emergence from a swimming pool, in a betwitching red bathing suit, of Katharine Ross as Ann Kurth. "I need you to know me, Ann, the way nobody else ever has," Hill tells her at ye olde fishing hole.

Elliott has never seemed remotely formidable as an actor before -- merely competent in beefy, drawly roles that didn't require introspective explorations. Here he puts together a masterful portrait of a man who thinks of himself as God's masterpiece, a man who soaks himself in amenities and spares nothing in the pursuit of self-satisfaction. He is Mr. Hyde as the ultimate epicure, a creature who never tires of finding new ways to enhance his opinion of himself.

Unfortunately, the sinister subtleties of this characterization tend to vaporize in part two, when Elliott becomes more and more the stock psychotic monster. When McGreevey and Hale lock Ross in the house alone, with thunder and lightning bashing and crashing and Elliott stalking Ross, the film's fairly rich sense of social context tends to go blooey.

These scenes, including an eventful Cadillac ride in which the doped-up doc threatens his second wife with a syringe full of God-knows-what, are the most viscerally effective in the picture, but in the first half, there are enough telling, nicely observed details of the sweet life in Texas to put "Dallas" to shame and suggest that, in depicting this American tragedy, McGreevey and Hale may have been aspiring to ramifications along the lines of "An American Tragedy."

Griffith's performance is like Burt Lancaster's in the current "Atlantic City"; one not only finds much to admire in it, but it brings to mind a career full of admirable work, if not always in particularly imposing vehicles. cWhen, near the end of part one, Ash Robinson is approached by Hill at the cemetery where Joan has just been buried, and the old man, out of bitter bereavement, shoves Hill and barks "Get away! Get away from us!", it is a chilling and powerful moment.

Fawcett leaves the fluffy sex kitten image way behind and makes Joan Robinson believably sad and victimized, with just a trace of the spoiled brattiness one would expect of an oil millionaire's beautiful daughter.

The time seems always to be ripe in America for a juicy, nasty murder story involving the rich; only three days after "Texas," NBC will offer a two-part dramatization of the Jean Harris trial. But to credit of those who made "Murder in Texas," the story isn't played merely as titillating gossip. The filmmakers walk a deft line between dry docudrama and voyeuristic sleazer.

For Griffith and the much-maligned Fawcett, the film constitutes another victory in one case and artistic vindication in the other. But there are no weak links to "Murder in Texas," and if the resolution doesn't fulfill the promise of the first two hours, the film is still one of the best made for television this season, and almost unceasingly gripping to watch.