
In 1971, MacDonell wrote Flight Characteristics and Stain Patterns of Human Blood, the first authoritative BPA training manual. MacDonell, who is credited with establishing the profession of Bloodstain Pattern Analysis (BPA).

His testimony helped win Sheppard’s freedom. Paul Kirk, a criminologist at the University of California, Berkley, conducted a reconstruction of the crime scene and provided the first expert testimony interpreting for the jury patterns of cast-off and impact spatter bloodstains that were present at the crime scene. Lee Bailey, gained fame as a criminal defense lawyer by winning an acquittal on re-trial. Supreme Court vacated the original conviction because of pre-trial publicity that made it impossible to receive a fair trial. This famous case inspired the TV series The Fugitive (1963-67) and the 1993 movie, starring Harrison Ford. Sheppard had been convicted in 1954 of bludgeoning his wife to death in her bed, but maintained his innocence, claiming the attack was perpetrated by an intruder.

The first use of blood stain analysis in an American courtroom occurred in 1966, in the re-trial of Sam Sheppard, an Ohio physician who spent over 10 years in prison before being freed.
