Ronald Walter Dobson used to be known by his CB handle. "Hello, I'm Snapshot," he would say from his state police radar car. "I'm on the air, and I'm gonna take your picture when you go by."

In and around this Calvert County seat, where he and other state police provide the only local law enforcement, trooper Dobson was widely-known and, by all accounts, generally well-liked, the kind of officer who would rather give someone a warning than a ticket. He was the son of a retired state police barracks commander and the nephew of another state trooper on Maryland's Eastern Shore, where he grew up.

His enthusiasm for the CB radio brought him into chance contact with many people on and beyond this Southern Maryland peninsula wedged between the Chesapeake Bay and the Patuxent River. Among them was Rexine Plummer, the woman he lived with in a home he built in the woods several miles south of here. He reached out to citizens through community activity that included organizing a CB hotline to aid motorists and others in distress.

But gradually, in a long, slow process that no one seemed able to reverse, Dobson began to withdraw and decline, battling mental illness that cut him off from almost all around him.

His downhill slide appeared to begin with a bizarre incident in which he was bitten or scratched by a bat that flew at him in a dark building where he was searching for prowlers.

It ended abruptly and terribly on a Friday morning in late November, when Dobson, 36, murdered Plummer with a shotgun in the woods outside their home, then turned the weapon on himself.

The tragic ending of Dobson's life left his many casual and close friends saddened, but not surprised. Plummer's death came as more of a shock -- it had become for many almost a foregone conclusion that Dobson eventually would take his own life, but that he would take another's life had not.

Although many of his relationships with women ended in violent eruptions of a temper he otherwise kept under control, Dobson's friends remember him as a gentle person, quiet at times almost to the point of shyness. A man of medium build with strawberry blond hair, he loved life, children and stray animals.

"He was probably the best friend anyone would want to have," said Debbie Goldstein, sports editor of the weekly Calvert Independent.

Steve Spellman, son of former congresswoman Gladys Spellman, lives in the county and was casually acquainted with the former trooper. "Treat him kindly," he told a reporter inquiring about Dobson. "He is Everyman. He is the man next door."

Beneath Dobson's calm, often smiling exterior, according to those who knew him best, was hidden pain. He missed his children, who lived half a continent away, a distance he felt he could not bridge because of his emotional ill health. And he had a difficult love-hate relationship with his father, whose standards of behavior and performance he felt he never could meet.

Today, Walter Dobson speaks of his only son, the second of three children, with sadness but also with pride -- a sentiment that Ronald told friends he had never seen his father display in his presence. "I just can't ever seem to please my dad," Ronald Dobson told his friend Bobby Hance, over and over again.

In his final days, he recalled the time his father had locked him in jail one night to teach him a lesson. The incident left a deep emotional scar that he shared with few people. His father dismisses the incident as minor punishment for an adolescent affront, possibly an incident at school involving a girl.

Over the years Dobson had problems with a broken marriage, then with girlfriends, and with at least one of his police superiors, a man who Walter Dobson said previously had worked for him on the Eastern Shore. The elder Dobson said he had been critical then of the man who was later to be his son's superior.

By all accounts, however, Ronald Dobson kept his problems largely under control until the incident with the bat and a series of painful rabies shots that followed.

"His life fell apart after the shots," said his former wife.

More than a year later, he began seeing a state psychiatrist, and received antidepressant tablets. The combined effect of the antidrepressants and the alcohol, Dobson wrote in a spiral-bound journal he kept at the time, "was disastrous."

His "production and efficiency were getting worse," he noted, and his superiors criticized his work "several times." He had crying spells and became convinced that his career as a state trooper was over.

Despite his wish to remain on the force, he filed for a disability retirement in April, 1978.

In a letter to Dobson's lawyer that became the basis for the disability claim, Dr. Max Collier, of University Hospital, said that while he could not conclude "definitively" that Dobson's "depressive, impulsive behavior" was "related solely" to his job, "one does note Mr. Dobson was traumatized, i.e, bitten by a bat and the subsequent anti-rabies shots. It is our impression that this psychological trauma was one of the immediate precipitating factors . . . . "

That November, the state retirement board approved a two-thirds pension, apparently conceding without protest Dobson's claim of job-related disability.

In those uncertain days before retirement, Dobson suffered a humiliation about which he remained bitter to the end. Deeply depressed, he had sought to drive to Missouri to see his children. His ex-wife, frightened by his surprise phone call announcing his visit, contacted the Maryland state police. They stopped Dobson on I-270, near Frederick.

As he later recalled the incident in his journal: "I was brutalized, snatched out of my car, handcuffed, placed in jail." Charged with no crime, he felt that his constitutional rights had been violated and he wanted to sue the state. No lawyer would take the case.

"I told him because the principals are people I have to deal with locally, it wouldn't do me any good," said Thomas L. Starkey, a Prince Frederick attorney.

State officials declined to comment on the incident.

After retiring, Dobson had several scrapes with the law, "going out and getting drunk and mouthing off, disorderly conduct, minor stuff," according to Starkey, who represented him in some of those cases. Dobson became convinced that Lt. Norman Mobrey, his former boss on the force and the person with whom he had clashed, was out to get him.

"I became so paranoid, I stayed in my house except to get groceries," the former trooper wrote in his journal. "I became paranoid every time I saw a police car."

Mobrey declined to be interviewed for this article.

Larry Lamson, then a lawyer and now a judge, insisted as a condition of representing him at that time that Dobson hand over his firearms: two pistols and a shotgun. A year ago, Dobson asked for his shotgun and Lamson returned it to him.

"He came in moaning and groaning about wanting to use it for the hunting season, and I had no right to keep it," Lamson said. It was the weapon by which Dobson and Plummer would die.

Lamson, meanwhile, had referred Dobson to Dr. Frank Gunzberg, a St. Mary's County psychologist who Dobson saw weekly from May, 1978 to October, 1979. Sometimes Dobson and his girlfriend went together.

Gunzberg, in turn, referred Dobson to a nutritional specialist in Rockville. That visit led to Dobson's decision to seek institutional help. With $5,000 loaned to him by Lamson, Dobson checked into the Psychiatric Institute of Washington, then entered Coral Ridge Psychiatric Hospital, a small, private institution in Florida.

He was admitted to Coral Ridge for chronic depression on March 7, 1979 and released March 29, with his condition "improved" and his prognosis "fair." He returned home with a new faith: the gospel of health. Vitamins were the road to recovery, he told trooper Tom Hejl, with whom he had once roomed and who later would have the thankless task of handling the murder-suicide scene.

"He even had me taking those damn vitamins," said his father.

With missionary zeal, Dobson also ministered to Bobby Hance, insisting that his friend, a cripple who uses crutches, could walk "like normal people" if only he took vitamins.

"I'm the way I am and that's it, but I didn't want to hurt his feelings," Hance recalled. He also remembered something else about Ronnie after his return from Coral Ridge: "He had a strange, cold look in his eyes and it never went away. It was like he was staring into space."

Dobson held down jobs driving a flower truck and selling wood stoves, and he did volunteer work at Calvert Memorial Hospital. He talked about studying oceanography, but dropped it. He could be lucid and engaging, or rambling and creepy. Sometimes, he spoke of how the moon was made of steel and was hollow, with another civilization living inside, described visits from outer space, or propounded conspiracy theories of vested interests pushing the United States into limited nuclear war for their own ends. And he attributed his own situation to sinister forces. Some cried for and with him; others felt uneasy in his presence.

There was much that Dobson kept to himself, but he was not alone. After his 1975 separation and the divorce in 1977 came a succession of girlfriends.

Vernie Freeland was living with him when the bat incident occurred in June, 1976. She went with him to Baltimore, where he received his initial shots, and then watched his health and their relationship deteriorate. She broke off with him on New Year's Eve, 1976, after he appeared drunk on her doorstep and, she said, "smacked the crap out of me."

He met Plummer about a year ago, friends say. She was 28 and twice divorced, with a son, 8-year old Christian. Soon after they met, she moved in with him, worked two or three days a week in Calvert elementary schools and became a den mother of Cub Scout Pack 938.

They lived in the compact three-bedroom house he had built on two wooded acres off a country road in a place called Island Creek.

"He was very good with the boy, just like a father," a friend of Plummer said. On at least one occasion, Plummer used Dobson's last name in paying a traffic ticket. Often, they would go jogging together.

They also would fight. Neighbor Nancy Lowe said Plummer's son told her last summer that he and his mother were getting ready to leave because Dobson had beaten Plummer. But they did not leave, then. Plummer later rescheduled her departure for February, hoping to land a permanent part-time teaching position that would provide the wherewithal. This was her secret plan, which she kept from Dobson until the night before her death.

The week before, he had phoned Gunzberg, his therapist, and scheduled his first appointment in two years, for Wednesday, Nov. 25, the day before Thanksgiving. On Saturday, the 14th, he had visited Carolyn Kitchin, a courthouse employe, and was, she recalled, "in a good mood, just like he was years ago." He told a friend that he and Plummer had a one-year marriage contract due to expire soon, after which he said he would move to a health food commune in Oregon. He seemed upbeat about it, his friend said.

At home, his mood was different. For three days, he had been pacing and unable to sleep. He wouldn't talk to Plummer, and every time she left the house, he followed her.

Bonnie Mattingly knew Plummer through the Cub Scouts and had invited her, Ronnie and Chris for Thanksgiving. The two women had been on the telephone together for half an hour the night of Nov. 19, when Plummer excused herself. Dobson had taken Chris into the bedroom to have a "religious discussion" and had emerged full of apocalyptic gloom.

Plummer later called Mattingly back and, according to Mattingly, gave her the following account of what happened that evening: Complaining of chest pains, Dobson had said he was not long for this world, that he would meet the following week with Jesus. Plummer's son, he said, was his reincarnation. Plummer calmed Dobson and got him to sleep. She also discussed the possibility of leaving.

"Mommie," she said her son had told her solemnly, "Ronnie needs our help."

Mattingly's husband Dan also talked to Plummer that night and tried for 15 minutes to persuade her to leave at once. But Plummer refused. "She was afraid he Dobson was going to commit suicide," Bonnie Mattingly said.

It was shortly after seven the next morning when Nancy Lowe heard what she described as a "continuous blood-curdling scream."

"I thought it was a siren at first," she said. "I saw both of them, two figures. Next, I heard a 'boom, boom.' I did not look to see. I shut the door and pulled the curtain down."

Looking out her bathroom window, she saw Dobson, walking and holding the shotgun with one arm and Chris with the other. Then Dobson was running into the woods, with Chris trailing behind. She called the police. A few moments later, Chris wandered out of the woods and into another neighbor's house.

The troopers found Plummer barefoot by the road, clad only in her nightgown. A hundred yards away through the woods, they found Dobson, wearing blue jeans and a bathrobe, a fatal wound in his head, the shotgun at his side