This idea of an alibi is of recent origin.  Would Samuel Knapp have gone to sea if it were then thought of?  His testimony, if true, was too important to be lost.  If there be any truth in this part of the alibi, it is so near in point or time that it cannot be relied on.  The mere variation of half an hour would avoid it.  The mere variations of different timepieces would explain it.

Has the defendant proved where he was on that night?  If you doubt about it, there is an end of it.  The burden is upon him to satisfy you beyond all reasonable doubt.  Osborn’s books, in connection with what the young men state, are conclusive, I think, on this point.  He has not, then, accounted for himself; he has attempted it, and has failed.  I pray you to remember, Gentlemen, that this is a case in which the prisoner would, more than any other, be rationally able to account for himself on the night of the murder, if he could do so.  He was in the conspiracy, he knew the murder was then to be committed, and if he himself was to have no hand in its actual execution, he would of course, as a matter of safety and precaution, be somewhere else, and be able to prove afterwards that he had been somewhere else.  Having this motive to prove himself elsewhere, and the power to do it if he were elsewhere, his failing in such proof must necessarily leave a very strong inference against him.

But, Gentlemen, let us now consider what is the evidence produced on the part of the government to prove that John Francis Knapp, the prisoner at the bar, was in Brown Street on the night of the murder.  This is a point of vital importance in this cause.  Unless this be made out, beyond reasonable doubt, the law of presence does not apply to the case.  The government undertake to prove that he was present aiding in the murder, by proving that he was in Brown Street for this purpose.  Now, what are the undoubted facts?  They are, that two persons were seen in that street, several times during that evening, under suspicious circumstances; under such circumstances as induced those who saw them to watch their movements.  Of this there can be no doubt.  Mirick saw a man standing at the post opposite his store from fifteen minutes before nine until twenty minutes after, dressed in a full frock-coat, glazed cap, and so forth, in size and general appearance answering to the prisoner at the bar.  This person was waiting there; and whenever any one approached him, he moved to and from the corner, as though he would avoid being suspected or recognized.  Afterwards, two persons were seen by Webster, walking in Howard Street, with a slow, deliberate movement that attracted his attention.  This was about half-past nine.  One of these he took to be the prisoner at the bar, the other he did not know.