The autopsy on 5-year-old Edward Coffman found that he had several open wounds on his head and body, and neighbors in Baltimore County told police that they had seen the child's mother, Diane Coffman, spanking him.

But that was 1972, when authorities were far less schooled in the dynamics of family violence than they are today. The investigation went nowhere.

Diane Coffman told police that the death was an accident, that the boy fell in the bathtub -- that it was not a homicide, that he was not beaten.

The Maryland medical examiner's office labeled the manner of his death "undetermined." The file went into a cabinet and, in time, the death of Edward Coffman on Aug. 4, 1972, faded from official memory.

Until this summer, when an e-mail came to police from Edward Coffman's younger brother, prompting detectives to dig out microfilm of the old file. The e-mail was from Richard Coffman, now 35, who was 3 when his brother died. He said he did not think it was an accident, according to police. He said he thought his mother did it.

Once detectives and the medical examiner's office looked at the case file and autopsy results, in light of what they know today about the signs of child abuse, they concluded that Edward Coffman had been a homicide victim, authorities said. This week, Diane Coffman was arrested in Florida and charged with first-degree murder.

"Back in the 1970s, people were not as sensitive or attuned to those matters. It may have never crossed their minds that she could be a suspect," said Julie Drake, head of the family violence unit in the city prosecutor's office in Baltimore. "Children in the past were viewed explicitly as the property of their parents."

Diane Coffman, a receptionist in a dental office, was arrested Tuesday near her home in DeLand, Fla. She was released on $25,000 bail yesterday by a Baltimore County judge.

Coffman's attorney, Domenic R. Iamele, said his client had been living a quiet life in Florida after moving there three years ago with her husband, Darryl Coffman, the father of Edward and Richard Coffman. Darryl Coffman, who manages the frozen food department of a Wal-Mart, could not be located for comment yesterday.

Diane Coffman "was shocked when they came for her in Florida," Iamele said. "She didn't do this. She is completely beside herself at the thought she is being accused in his death." He said she plans to return to Florida while awaiting further legal proceedings in Baltimore County.

Iamele said that Richard Coffman, who could not be located for comment, is an angry son who cut his ties with his mother. "This story has kind of a Shakespearean backdrop. You have a disgruntled son who has divorced himself from his parents, particularly his mother," Iamele said. "There's been some tension there."

Police declined to say specifically what was in the e-mail that Richard Coffman sent, other than that it concerned his mother's character and events after his brother's death.

At the time, Diane Coffman had told police that Richard and Edward Coffman were taking a bath together and argued over toys. She said Edward fell, striking the right side of his face on the tub. The mother said that she placed an ice pack on her son's face and that he complained of an earache. She said she put him to bed at 8:30 p.m.

She checked on him while he was sleeping, she said, and at 4:30 a.m., she discovered he was not breathing. By the time police got to the house, the child was dead. Officers noted that Edward Coffman was bruised above and below his right eye, with another bruise on his left temple. Later that day, medical examiner Ronald N. Kornblum performed an autopsy and detailed 17 different injuries to the boy. He wrote that the wounds to Edward Coffman's head were "multiple and of varying ages."

Kornblum ruled the cause of death as a trauma and the manner of death as undetermined. But these days, experts take a different view of such autopsy results. "We now have more research that shows that many of these child injury incidents are not accidental," said Drake, who is not involved in the case.

After Richard Coffman approached police about his mother, Maryland's chief medical examiner, David R. Fowler, reexamined the case.

Fowler concluded last month that the story Diane Coffman told police did not square with his medical knowledge. He told police that Edward Coffman would have become unconscious no more than two hours after the fall in the tub described by his mother, not almost 12 hours later.

Fowler changed the ruling on the manner of death. After 32 years, Edward Coffman was declared a homicide victim.

Diane Coffman