From the artist (Trooper Bryant) of newly released, relevant sketch:
Master Trooper Taylor Bryant, a sketch artist with Indiana State Police who drew the new sketch,
told IndyStar a sketch is based on how a particular witness describes the suspect. If there are several witnesses, Bryant would draw a sketch for each description. Bryant did not draw the sketch that police released in July 2017.
"The witness is the main focus. So there’s no input from law enforcement at all in the generating of a sketch, other than my presence as the artist."
Bryant uses a "facial identification reference sheet" that has a list of different categories, from head shapes to different eyebrows and noses. The person will describe the suspect based on those categories. "(It's) easier to do that than to describe (the suspect) using just words," Bryant said.
The sketches are not exact, Bryant said. The renderings are a "ballpark estimation of what the person looks like."
The sketch released on Monday was drawn by Bryant on Feb. 17, 2017, a few days after the victims' bodies were found. The picture was based on the description of a person who saw something that the person felt needed to be reported, according to Bryant.
Delphi murders: New sketch of killer, video from Libby's phone released
ETA: Artist Trooper Bryant makes it clear that his drawing is from one witness only, and offers technique details as if to distinguish his method from that of the suspect sketch first released by LE.
Makes me wonder if sketch first released was not a composite sketch built from the accounts of several witnesses interviewed between Feb - July 2017, and LE favored this approach for the public release.
MOO