For Stephanie Roper, the last weekend of her life was to have been a time for the hard-working college senior to escape school pressures, visit old friends and relax in her close-knit community in Prince George's County.

Instead, the 22-year-old Frostburg State College senior was abducted, tortured and slain, and the savagery of her death seems to illustrate the worst of random violence. "I know it happens every day," her mother Roberta Roper said this week. " . . . Why did she have to be there when such evil came along?"

For the Roper family, of Croom in southeastern Prince George's County, there was the additional shock in discovering the details of their daughter's death on television, despite efforts of police to shield them.

"Without warning, we were given all the brutal facts," said her mother. "Thank God, her grandparents weren't there," she said.

Roper was last seen after a night of visiting nightspots in Georgetown with a childhood friend and college roommate. She dropped off her friend at her Clinton home at 3:15 a.m. on the morning of April 3. Having planned a day of shopping with her mother, Roper decided to go home.

But Roper never made it. Her orange Dodge Omni was found parked just over a mile from her friend's home, on a shoulder of Floral Park Road in rural Brandywine. It had three flat tires, a broken rear axle and the doors were locked. Police said she had had a minor accident, hit a tree and run over a stump.

"I didn't even begin to worry" when she didn't return, her mother said later. The two friends would often stay at each other's home after a late night out. But when her daughter didn't arrive by noon, her mother called the friend. Then she called police.

The young woman's body was found eight days later, more than 40 miles away, in an all-but-deserted marsh in the Oakville section of St. Mary's county. The state medical examiner ruled the cause of death was a gunshot wound in the head.

The St. Mary's state's attorney said Roper fell asleep at the wheel and that she was not intoxicated. Police theorized that passersby abducted Roper on the pretext of offering the stranded woman help. Maryland State Police told the Ropers their daughter had been shot. But what the Ropers didn't know, and what they found out later, was that she had been raped repeatedly, beaten with a logging chain when she tried to escape, and then shot in the forehead with a small-caliber rifle. She had been drenched with gasoline, set afire, and abandoned in six inches of water from the nearby Patuxent River. Her body was unrecognizable to those who found her.

"My wife got sick," said Sgt. Charles Dammann, head of investigations for the Maryland State Police at Leonardtown, who told her about it to reinforce the idea that you stay in your car if it breaks down.

"My other daughter said to me," Roberta Roper said, " 'Our family shows stray dogs more dignity and caring than she was ever shown.' "

Maryland State Police Cpl. Thomas Bowers, who informed the family at 4:30 a.m. Monday, made the decision "not to go into the gruesome details."

" . . . We didn't want them to hear it on the radio," Bowers said. "We told them she had been murdered and shot. They were upset and didn't inquire further. It's traumatic anyway, as you might imagine."

Bowers had worked on the case throughout the night and had not seen the press releases, which were prepared by the state's attorney's office. "We fully intended to go back later, after the funeral, and prepare them for the trial, where it was all going to come out," said Bowers. "We didn't know they were going to release it."

But the events of the day moved more swiftly than police expected. Acting on a tip relayed to the Prince George's police, the Maryland State Police found the body at 8 p.m. Sunday night. Three hours later, they arrested Jerry Lee Beatty, a 17-year-old high school dropout, at his brother's home in Waldorf. Early next morning, they had arrested Jack Ronald Jones, 25, of Queentree Road, who was living with his wife and 6-year-old son only a few hundred yards from where Roper's body was found and where she allegedly was killed. Until November, he lived with his parents on Floral Park Road, less than a mile from where Roper was abducted.

Beatty was charged as an adult and both men are being held without bond at the St. Mary's jail in Leonardtown.

According to C. Clarke Raley, the St. Mary's state's attorney, Beatty told an acquaintance what he had done. "The acquaintance found that he was enormously bothered by it," said Raley, "He went to see a pastor about it, and the pastor encouraged him to go to the police."

Beatty gave his father's home as an address. But his father said his son had been living wherever he chose, including long stretches of time when Beatty lived with Jones, his long-time friend. Beatty's relatives said that his temperament changed after his mother and brother died within two months of each other in 1977.

"After Mom died," said his sister, Judy Reamy, "he thought he could run everybody like he chose, talk to everybody like he wanted. I guess he felt nobody cared."

Many people cared about Stephanie Roper, and for the last few days her family has seen a stream of neighbors and relatives who are letting them know that. These people, the family said, reflect the best human instincts. Students at Frostburg State, in Allegany County in Western Maryland, held a prayer vigil for her and are planning a memorial service next week.

When the family was still searching for their daughter, neighbors contributed to a $10,000 reward fund. That money now will be used for a scholarship in her name.

"I've been asking myself," said Roberta Roper, " 'What is there to learn?' If we say we believe in the Resurrection, we have to try to be people of faith right now. We can't let this destroy us. I don't think she would have wanted us to fall apart."