The young man, William “Duff” Armstrong was accused of murdering James Preston Metzker just before midnight on 29 August 1957.
Jack Armstrong, Lincoln’s friend and Duff’s father, had just passed away and Abraham offered his services without pay to help Jack’s widow during the difficult time she found herself in.
During the trial Armstrong was accused of murdering Metzker with a slung-shot – a maritime tool which consisted of a rope with a heavy weight on one end that was used to cast a line from one place to another.
The principal witness for the prosecution, Charles Allen, claimed that he witnessed Duff killing Preston from 150 feet away.
When Lincoln asked Allen how he could identify Armstrong at such a distance just before midnight in the dark, Allen said, "By the light of the Moon."
Lincoln must have anticipated his response, because he produced an almanac and paged to August 1957. Using the almanac he proved to the jury that the moon was in its first quarter and, at the exact time Allen claimed to have witnessed the murder, the moon was about to set!
The jury agreed with Lincoln that the moon could not possibly have produced enough light for Charles to clearly identify the killer at such a distance, and Duff Armstrong was acquitted!
