John Francis Knapp And Joseph Jenkins Knapp Trials: 1830

Webster, however, raised the question of whether Francis and Joseph Knapp could be legally considered as "present" during the murder so that they could be convicted. True, the Knapps had been 300 feet away in the street, but they had been there to help Crowninshield:

To constitute a presence, it is sufficient if the accomplice is in a place, either where he may render aid to the perpetrator of the felony, or where the perpetrator supposes he may render aid. If they selected the place to afford assistance, whether it was well or ill chosen for that purpose is immaterial.

The perpetrator would derive courage and confidence from the knowledge that his associate was in the place appointed.

Webster's definition of presence would include Francis Knapp and, by implication, ultimately anyone involved in a murder who had come near enough to the scene of the crime to be considered "aiding and abetting" the actual murderer. Dexter argued strenuously for a conservative approach, that only physical presence at a murder could mean legal presence. According to Dexter, Francis Knapp would have to have been in Captain White's bedroom with Crowninshield to be considered present and found guilty:

To make a man a principal by aiding and abetting in a felony, he must be in such a situation at the moment when the crime is committed, that he can render actual and immediate assistance to the perpetrator; and that he must be there by agreement, and with the intent to render such assistance.

Faced with these powerful but opposing legal arguments, the jury at first could not reach a verdict, but ultimately it found Francis Knapp guilty by the close of the July Term. Knapp was going to hang, and now it was his brother Joseph's turn to be tried.

Joseph Knapp's trial took place during the Court's November Term of 1830. Joseph Knapp had testified against Crowninshield at the arraignment, but he refused to testify against his brother Francis at his trial. Therefore, the state dropped its earlier promise to give Joseph Knapp immunity and put him before Webster to be prosecuted. Dexter and Gardiner had lost the debate over the legal definition of presence at Francis Knapp's trial, so in Joseph Knapp's trial, they shifted their attack to whether the Knapps had been close enough to aid and abet Crowninshield. The trial record states:

The prisoner's counsel now offered evidence in regard to the place at which the principal … was stationed during the perpetration of the murder, their object being to show that in that situation it was impossible for him to aid and abet the person who was actually striking the blow.

The jury rejected Dexter and Gardiner's last-ditch attempt to save Joseph Knapp, however, and by the close of the November Term found him guilty.

Francis and Joseph Knapp went to the gallows. Having successfully convicted them of murder, the state of Massachusetts also tried and convicted George Crowninshield, a brother of Richard's who had a minor role in the whole affair, of aiding and abetting Captain White's murder.

The whole Francis and Joseph Knapp affair would have gone down in history as a typical sordid murder if it had not been for Daniel Webster's eloquence. Webster persuaded the judges and the jury to expand the boundaries of an accessory's liability for murder. Once thus expanded, the old common law restrictions that would have prevented guilty men such as Francis and Joseph Knapp from being brought to justice were, over time, eventually swept away.