Lewin Carlton Powell III is an honor student who played in the jazz band at McDonogh School. Neighbors in Towson''s Riderwood community saw the 16-year-old boy as responsible and polite.

His mother, Donna Rosemarie Campbell-Powell, worked for the county, and colleagues said she spoke proudly of her son.

But a man who lived next door said their relationship was sometimes tense. And on Tuesday afternoon, the teenager would later tell police, a quarrel about the teenager''s grades spiraled to the point that he reached for a baseball bat.

He told investigators that he beat his mother to death, then hid her body. And the next morning, according to court records, as his father slept on the couch, the teenager grabbed the bat again.

Yesterday, Powell was ordered held without bail to await trial on adult charges of murder and attempted murder. At the same time, grief counselors were dispatched to both McDonogh and the Baltimore County budget and finance office, where the 39-year-old mother worked. The father, Lewin Carlton Powell Jr., having been treated for his injuries at Sinai Hospital, also stopped by the county finance office yesterday.

Lynn McKain, a McDonogh spokeswoman, said, "This is a really sad and tough day. Our deepest sympathies go out to Lewin Powell''s family for the tragedy they suffered."

It is the second time in three months that a county teenager has been accused of killing a parent. The two cases account for half of Baltimore County''s 10 homicides this year.

Police were called to the Powells'' home on Alston Road at 10:03 on Wednesday morning.

Campbell-Powell had not shown up for work or called to say she''d be late, and her co-workers were worried, said Keith Dorsey, director of the office. The assistant claims adjustor, who impressed co-workers with her punctuality and impeccable wardrobe, was always at her desk by 8:15 a.m. - at the latest.

Two of Campbell-Powell''s co-workers called McDonogh and learned that the woman''s son was absent, too. More worried, they drove to her house to make sure everyone was OK, Dorsey said.

The woman''s Toyota Corolla was in the driveway of her split-level home, but no one answered the door. So the co-workers called police.

When officers arrived, they found the younger Powell and his father in the backyard. The father was bleeding from "significant wounds" to his head, according to court records.

"Thank God you''re here," the elder Powell told the officers, according to court records. "My son killed my wife."

Police found the woman''s body in the garage, covered with a blanket and some debris. She had suffered multiple blunt force injuries. And detectives found what appeared to be bloodstains in several locations throughout the house, according to court records.

The father later told police that he had worked until midnight, driven home and gone to sleep on the couch. He awoke to find his son hitting him on the head with a baseball bat. He tried to run out of the house but was stopped by his son, who blurted out during the struggle that he had killed his mother, according to court documents.

The boy later confirmed to police detectives that he killed his mother and intended to kill his father as well, according to the documents.

Someone who answered the door yesterday evening at the Woodlawn home of Campbell-Powell''s relatives said the family was too distraught to discuss the incident.

Paul Kozloski, who lives next door to the Powells, described the mother as a good neighbor but said she seemed too controlling and critical of her son, who recently seemed especially sad.

"He had, for someone his age, the shortest leash you could have on a child," said Kozloski, a retired probation officer who has lived in the neighborhood for more than 20 years. "I never saw a friend, except his cousin, over there at the house. It was all about academics and sports, and it was pressure, pressure, pressure. ... I think he snapped."

The neighbor said one of his teenage daughters told him that Powell recently expressed concern about telling his mother that he had earned a C in his Advanced Placement history class.

Powell, a sophomore honors student at the Owings Mills private school, has attended McDonogh since sixth grade.

McKain, the school spokeswoman, said school officials were not aware of anything unusual going on in Powell''s life in recent days.

"We were as surprised and shocked as everybody," she said.

Saying she could not discuss his academic record for privacy reasons, McKain described the teenager as an "academically capable" student who was enrolled in honors and Advanced Placement courses. Many of his classes required a teacher''s recommendation, meaning that he would have had to be at the top of his class to take them, she said. And although Powell had played baseball in previous years, he was not on the school''s team this year.

His mother took a job as an assistant claims adjustor with the county government a little less than a year ago, leaving a position with Blue Cross Blue Shield.

"She was a class act - the way she spoke, the way she dressed, always impeccably, the way she behaved," said Mary Ellen Niles, an assistant county attorney and supervisor of the claims management unit where Campbell-Powell''s job included paying medical bills of county employees injured on the job.

"Donna was the type of person people got to know quickly," she said. "She was generous, giving, dependable - easy to get along with."

Several colleagues recalled the woman''s dedication to and pride in her son, Niles and Dorsey said.

Powell is the second Baltimore County teenager this year to be charged with murder in the death of a parent. In February, Nicholas W. Browning, a 16-year-old Dulaney High School sophomore, was charged with killing his parents and two younger brothers as they slept in their Cockeysville home.

A hearing is scheduled next month on whether Browning, who was 15 at the time of the killings and remains in the county jail, will be tried in adult or juvenile court.

Because Powell was 16 years old at the time of his mother''s death, he will not be eligible to request a waiver back to juvenile court.

Experts say that the murder of a parent at the hands of a son or daughter is rare in this country, occurring only 250 to 300 times a year. That amounts to about 1.5 percent of all killings.

In 2006 - the most recent year for which data were available from the Federal Bureau of Investigations - 115 mothers and 114 fathers were killed by one of their children, both adults and juveniles, nationwide.

But adolescents are more likely to kill a parent than grown children or younger children, said Dr. Michael Arambula, a Texas forensic psychiatrist.

These killings may seem to be out of the blue, Arambula said, but investigators have found that there is often mounting tension in those homes.

"It''s kind of like a pressure cooker," he said, comparing the cycle to a battered-wife syndrome. "Then there''s something that breaks the camel''s back."