The Supreme Court ruled yesterday that a state can use a single police photo in a criminal trial to get a witness to identify a suspect although the state admits that using the picture of one suspect rather than several suggests him to be guilty.

In a 7-to-2 decision, the court also held that the suspect was not denied the constitutional protection of due to process of law even though no emergency circumstances had required reliance on the showing of a single phot to a prosecution witness.

In the opinion for the court, Justice Harry A. Blackman wrote that "reliability is the linchpin in determining the admissibility of identification testimony."

He said the factors to be considered "include the opportunity of the witness to view the criminal at the time of the crime, the witness' degree of attention, the accuracy of his prior description of the criminal, the level of certainty demonstrated at the confrontation, and the time between the crime and the confrontation."

Dissenting, Justice Thurgood Marshall, joined by Justice William J. Brennan Jr., wrote, "The use of a single picture (or the display of a single live suspect, for that matter) is a grave error . . . because it suggests to the witness that the person shown must be the culprit. Why else would the police choose the person?"

He portrayed the decision "as no surprise to those who have been watching the court dismantle the protections against mistaken eyewitness testimony" that a triad of 1967 rulings had erected. "But it is still distressing to see the court virtually ignore the teaching of . . . those decisions and blindly uphold the conviction of a defendant who may well be innocent," Marshall said.

The case involves the 1970 arrest of known narcotics dealer Nowell A. Breathwaite after undercover Connecticut state policeman Jimmy D. Glover, accompanied by an informer, bought heroin from a man at the door of a Hartford apartment. At the time, Glover did not know the identity of the seller, but described him to other officers. Two days later, they showed him a photo of Brathwaite. Glover identified him as the seller.

At trial, the defense objected neither to admission of the photo into evidence nor to an in-court identification by Glover, who hadn't seen Brathwaite for eight months. The prosecution didn't explain why it hadn't shown Glover an array of photos or conducted a lineup.

Brathwaite and his wife testified that on the day of the sale he had not gone to the apartment because he had been at home ill (he later underwent surgery). A jury convicted him. His sentence was six to nine years.

He sought relief in the federal courts. The Second U.S. Circuit Court of Appeals struck down the conviction, holding that evidence as to the photo, which it considered unreliable in any event, should have been barred because giving Glover single photo to examine was unnecessary and suggestive.

Blackman wrote that the "corrupting effect" on the suggestive identification was outweighed by the "totality of the circumstances," including the "sufficient opportunity" of "a trained police officer" to view Brathwaite.

In his dissent, Marshall cited reasons for doubting the reliability of the identification, including the duration of the face-to-face transaction: as little as 15 to 20 seconds during which Glover was not always looking at the seller's face. The decision, he charged, "virtually grants the police license to convict the innocent."