A 21-year-old Prince George's County man convicted earlier this year of murdering a county policeman will learn this week whether he will spend life in prison or be sentenced to die in the Maryland gas chamber.

Harlow Brian Sails shot and killed 28-year-old Raymond Hubbard, an off-duty police officer, while fleeing with his brother and three friends after holding up a jewelry store at Iverson Mall on Jan. 28 last year.

Last week, Sails sat impassively as defense attorneys and prosecutors, aided by psychiatrists, attempted to weigh the value of his life.

Defense attorney Michael L. Gallavan told jurors that Sails suffered from drug use and had been using drugs on the day of the murder. Sails, he argued, was a confused and shocked man who did not know the man he shot was a police officer.

In such circumstances, Gallavan maintained, the "proper punishment in this case would be to sentence Harlow Brian Sails to prison for the rest of his natural life." Sails deserved to be punished, Gallavan said, "but not in the Maryland gas chamber."

Dr. Neil Blumberg, a psychiatrist for the defense, has testified that Sails has a below normal intelligence, with an I.Q. of 89. He said Sails' emotional condition seriously deteriorated three years ago when his father, a merchant sailor, was shot and killed while being robbed in Philadelphia.

Sails told jurors last Tuesday he was sorry for killing Hubbard. "I regret it," he said. "I regretted it from the day it happened, you know. My intentions wasn't ever to really kill nobody, but it happened. There's nothing I can do about it now. I'm sorry about that."

At the same time, Sails pleaded for his life: "I don't want to die," he said. ". . . . I know I'm wrong, but I still don't want to die."

Dr. Michael Spodak, testifying for the prosecution, said that from the age of 14, Sails had shown a tendency towards increasingly violent criminal behavior. He called Sails "emotionally unstable," with "poor impulse control" and said it was "likely" he would become involved in violent criminal behavior in the future. Spodak also said he did not believe Sails "has any real remorse for what he has done."

Prosecutor Arthur A. Marshall Jr. has argued that Sails is a danger to society even if he remains locked in prison. Currently in the county detention center in Upper Marlboro, Sails has been kept in "dead-lock" with his feet shackled 23 hours a day since Aug. 11, when he allegedly struck three guards over the head with a metal bunk post during a cell search.

Three other men, including Sails' 25-year-old brother Horacio, received life sentences last summer for their part in the killing. One other suspect is still at large. Sails, who lived in Riverdale with his girlfriend and 18-month-old daughter before his arrest, still faces several armed robbery charges.