Jurors who decided convicted police-killer Harlow Brian Sails should receive life in prison instead of the death penalty said this weekend it was clear almost as soon as they began their 40-hour sentence deliberations that they could not send him to the gas chamber.

Jurors, four of whom were interviewed by The Washington Post, said they spent nearly half that time debating one point: did Sails know, or should he have known, that the man wearing civilian clothes who he shot and killed was a policeman? An hour before reaching their verdict they agreed he should have known.

But in voting for a life sentence, the jurors took into account that Sails had never been jailed before and that he had not physically injured victims of previous armed robberies. And though prosecutors insisted Sails shot Hubbard "execution" style, the jury specificially disagreed, according to a verdict sheet they filed with the court detailing how they reached the verdict.

Jurors also said they believed Sails' unstable upbringing and "limited intelligence" were factors mitigating against giving him the death penalty.

In January, the same jury of six men and six women convicted Sails of shooting 26-year-old Raymond Hubbard, an off-duty Prince George's County officer, when Hubbard tried to stop a jewelry store robbery at Iverson Mall on Feb. 8, 1982. Sails still faces six separate armed robbery charges and three charges of assaulting jail guards.

The jury began its sentencing deliberations at 9:30 Wednesday morning, and returned shortly after 2 a.m. Friday, the first county jury to reach a verdict in a death sentence hearing.

One hour before they returned a verdict, two jurors were still pressing for the death penalty. But three jurors interviewed agreed the question of whether Sails would live or die was settled in favor of a life sentence by the time the jury had read the judge's instructions and their verdict sheets.

Michael Caffrey, a 31-year-old machinist from New Carrollton, said two jurors "would have never given the death penalty," and a hung jury would have forced Circuit Judge Howard S. Chasanow to sentence Sails to life. Foreman Melvin Williams, a 38 year-old personnel manager from Upper Marlboro, said the way the death penalty law, verdict sheets and judge's instructions were worded made it "almost impossible" to sentence Sails to death.

Some jurors said Prince George's County State's Attorney Arthur A. Marshall Jr. presented a poor case and that that Sails would never have been convicted of first-degree murder if he had not given a last-minute confession from the witness stand.

"Most of us thought the state did a pretty lousy job," said one juror, who asked not to be identified and who called the prosecution's psychiatrist "an insult" to the jury's intelligence.

When the jury's verdict was read to a tense and crowded courtroom, several jurors had tears in their eyes. Most of those in the courtroom were uniformed officers, who lined the courthouse corridors after the verdict and stared at each juror filing past.

One juror said he "was deeply resentful of the way they acted." Williams said it felt "eerie" to walk through the line, but said he sympathized with the officers.

Mahlron Curran, president of Fraternal Order of Police lodge representing county police officers, described his colleagues as bitter and disappointed. If police are to be reassured that the community appreciates their efforts, he said, the community must "have the fortitude and tenacity to put a cop-killer to death."