Shortly after nightfall on Jan. 30, 1974, a New York State Police investigator looked in the window of a family physician's examination room in the Village of Wappingers Falls.He saw the doctor repeatedly rape and sodomize an unconscious patient.

The physician is William A. Abruzzi Jr., who is widely known as "the Rock Doc" because he had ministered to the fallen at numerous rock festivals around the country. In 1966, the Food and Drug Administration stopped accepting his data from tests of experimental medicines after finding that he was in Austria when his office records showed him to be testing drugs in Wappingers Falls.

Two months after Trooper James Apolinaro saw Abruzzi assault the patient, a 28-year-old married woman who had expected to get a routine gynecological examination, a Dutchess County grant jury return a five-count indictment.

Abbruzi made a detailed statement to the district attorney about what he had done. Then he pleaded guilty to single count of sexual abuse in the first degree. Four ther counts - two involving the woman, and one each involving similar abuse of another woman and a 15-year-old girl - were dropped.

He drew an indeterminate sentence of up to five years. In addition, the state began proceedings to revoke his physician's license; the attorney general will hold a fifth and probably final day of closed hearings Nov. 4. Meanwhile, Abruzzi has stopped practicing and is living somewhere in upstate New York. He is married and a father.

Despite his guilty plea, the case is now before the Supreme Court, on petition of District Attorney John R. King. He wants the justices to review a ruling by the New York Court of Appeals that the state convincted Abruzzi with evidence obtained by Trooper Apolinaro in an unconstitutional, warrantless search.

The Supreme Court, which is in recess until Oct. 31, is expected to decide soon whether to hear arguments in the case. If it agrees to do so, it might clarify issues such as the definition of an unreasonable search within the context of physician-patient relationship, who the supposed beneficiary of that relationshi is, and whether a right of privacy protects a person while he is committing a crime against another person.

In order for the court to hear the casea, at least four of the nine justices must vote to review the lower-court ruling. No one knows whether they will, but a clue - possibly unreliable - is the justices' denial, on Oct. 3, of a petition by the State of Illinois for review of the reversal of a conviction of Chicago dentist Nicholas A. Polito for sexual molestation of an unconscius patient from whom he supposedly was extracting a tooth.

The legal differences separating the Abruzzi and Polito cases may be crucial, even though appellate tribunals in both held that the Fourth Amendment required police to have gotten search warrants.

In the New York case, for example, Trooper Apolinaro had no expectation whatsoever that he would see Abruzzi molest the 28-year-old woman; he hadn't even known she was there. In contrast, Polito's victim - his receptionist - had co-operated with police, who battered down the door of a windowless office in the expectation of catching the dentist in the act of raping her.

The Abruzzi prosecution originated in the summer of 1972, when a mother went to the physician for treatment of a neck rash. He imaginatively identified the cause as a tipped uterus requiring a gynecological examination. At his direction, she undressed and, covered by a sheet, lay down on an exrups. She could not see the "examination."

Abruzzi repeatedly told her to "relax" and to think about other matters while he engaged in what he claimed to be the only useful therapy. She said he felt penetration by what she assumed to be a medical instrument.

Afterward, concerned and suspicious, she went to her gynecologist, who found sperm. She then complained to the district attorney, as another woman did later.

The prosecutor then enlisted New York City policewoman Peggy Hopkins to survey Abruzzi's inner offices. She did so, saying she had cold, in late evening on Jan. 30, 1974.

Meanwhile, officer Apolinaro had gone to the back yard, put a seven-foot ladder against Abruzzi's combined home and offices, and climbed up near a window, so that he could keep an eye on Hopkins and protect her in event of sexual misconduct by the physician. Unexpectedly, he saw Abruzzi molesting another woman, the 28-year-old who had been rendered unconscious with an anesthetic.

For the trail court in Dutches County, the "controlling" circumstance legally justifying the officer's intrusion on Abruzzi's privacy was the "imminent danger" facing policewoman Hopkins.

Abruzzi, before pleading guilty, sought dismissal of the indictment on the principal ground that the evidence against him - Apolinari's observation of the rape - had to be suppressed because the officer had gathered, without a search warrant, even though the authorities had had ample time to get one.

The trial court disagreed, saying that it could not hold that Apolinaro had been required "literally . . . to blindfold himself to illegal acts committed in his plain view."

Why hadn't the state gotten a search warrant? It argued that, under court ruling, a warrant "may not be issued on the mere speculation that a crime may be committed sometime in the future."

By a vote of 3 to 2, however, an intermediate appellate court reversed the conviction. Notably, all five judges said that Apolinaro had made an unconstitutional search, although the dissenters agreed with the state that the basis for a search warrant, was so tenuous that it could not legally have been issued. Moreover, the dissenters said the record was insufficient to support a factual finding that Apolinaro had peeked through the window to protect Hopkins.

The key issue dividing the judges arose under the controversial exclusionary rule that says evidence gathered in an illegal search must be excluded as the fruit of a poisonous tree.

The majority said that the state, having failed to get a search warrant to "enter upon a private property and peep into a physician's examination room," could not use Apolinaro's observations to prosecute Abruzzi.

The dissenters said that the exclusionary rule does not taint evidence about "an independent crime - a crime committed in front of the investigator . . ."

They also termed it "anomalous" and "unearthly" that Abruzzi sought to suppress the evidence after making "a full statement in specific detail . . . of his sexual conduct . . . as the necessary foundation for his plea of guilty . . ."

Last May 12, the Court of Appeals voted 6 to 1 to uphold the reversal, thus leaving Abruzzi free.