Prince George's County prosecutor Arthur A. Marshall Jr. said last night he will consider seeking a new indictment against Jack Ronald Jones, the convicted killer of Frostburg State College art student Stephanie Ann Roper.

Marshall, speaking a day after a jury spared Jones from the death penalty in the murder, allegedly committed in Saint Mary's County, declined to comment on the jury's action, but indicated that it prompted his decision to consider the possibility of seeking a new charge in Prince George's.

"We probably wouldn't be taking as good a look at it as we are if the death penalty had been returned," Marshall said.

Although Roper was killed in Saint Mary's, authorities said the events that led to her death began in Prince George's. The slaying occurred during the early morning of April 3 after Jones and codefendant Jerry Lee Beatty, 17, who has not yet been tried, came upon the victim in her disabled car on a rural road in Prince George's. Instead of dropping her off at a friend's home as promised they drove her to an abandoned house in St. Mary's , where she was raped, hit over the head with a logging chain, shot in the head and set afire.

"The case emanated here," Marshall said last night. "It started in Prince George's. We want to look to see if we have a viable case."

The decision of the jury that Jones should be sentenced to life imprisonment rather than death appeared to stun the victim's parents who had regularly attended Jones' trial, which was held in Towson, Md.

"Obviously," asserted the victim's father, Vincent Roper, "the jury was swayed by emotions."

At the conclusion of jury deliberations Thursday night, Circuit Judge Walter R. Haile imposed concurrent sentences of life for both murder and rape and 20 years for kidnaping. With credit for time served since his arrest and with additional time off for good behavior Jones could be eligible for parole in about 12 years.

If Jones had been given consecutive sentences, he would not become eligible for parole for about 25 years.

"We have received a life sentence and we're not eligible for parole after 12 years," said Roberta Roper, the victim's mother. "Society has failed our daughter and may fail others again."

In deciding between the death penalty and life imprisonment the jury was required to weigh aggravating factors against mitigating factors concerning the crime and the suspect.

The jury accepted a number of defense arguments, among them that Jones was unlikely to pose a continuing threat to society, that he had cooperated with police after his arrest and that he showed remorse.