"He knows nothing about it," his lawyer, Edward D. Sohier, said. "There are the remains of a human body but we can no more explain how they came there than the government can."

At the end of the trial, the jury deliberated for two hours and 45 minutes. But despite Sohier's denials, they convicted Webster of murder in the first degree.

At first, Webster protested the verdict. He petitioned the government to, at the very least, reduce his sentence.

But then, on July 2, 1850, Webster admitted to the crime. He said he had become angry with Parkman and had grabbed the nearest object with which to hit Parkman. What he grabbed was a "stick of wood." The blow killed the professor.

The state's Committee on Pardons did not budge in its death sentence.

At 9:30 a.m., on August 30, 1850, in front of a hushed crowd of thousands at the Leverett Street Jail, John W. Webster was hung for the murder of George Parkman.

Today Webster's case is a textbook example at many law schools about conviction by "circumstantial evidence."

According to Sullivan, the cause helped establish many legal precedents. It also was important to the development of "effective definitions of 'reasonable doubt,' 'alibi,' 'murder,' and 'manslaughter,'" Sullivan wrote.

The Webster case, according to Edmund Pearson, the so-called "historian of homicide," is America's most celebrated murder