In the sketch recently released, some people including myself have noticed a slightly lazy right eye. I understand BG was walking carefully because he was on the bridge with uneven boards but is it possible he has always walked a little carefully, or even awkwardly if you will, due to a minor vision impairment?
Much has been said about the YBG's facial features, including his eyes, which others have noted to be 'hooded'. I did some research and found a genetic condition called Noonan Syndrome which can cause this. IMO YBG has many of the physical characteristics of this syndrome including:
-hooded eyes
-downward sloping eyes
-strongly arched eyebrows
-low set ears
-coarse and curly hair
-short stature (men average 5 foot 5")
This is an image I pulled from the internet which shows some of the features (look at the pointy chin, shape of the nasal folds, large forehead, and hairline--these remind me of BG). One characteristic of Noonan Syndrome is having a very wide neck, which BG does not appear to have--although with a hoodie, jacket, and possibly a scarf on, maybe his true neckline was not visible.
The article I got my information from said that the syndrome can be mild and the characteristics so subtle than some people do not look noticably different (BG might not be as severs as the image).
Just two points I wanted to make:
1. MAYBE BG has some type of disability/deformity which has impacted his development and personality. Perhaps he was bullied as a child, or overprotected by his mom because of his condition, and maybe has been unable to find a romatic relationship or a good job due to his syndrome, leaving him angry and/or depressed and feeling powerless in his life which was a trigger for the murders. Maybe Abby & Libby commented on him being 'creepy' because of his looks.
2. IF BG does have something like Noonan Syndrome he should have an extensive medical file. He was probably seen by multiple specialists as a child and teen, and would likely still require regular appointments with an optometrist. Talking to doctors in the local area and larger city centers to see if they have/had any patients matching this description could be an investigative angle for LE.
*I know this is a longshot, and in no way do I mean to imply that people with disabilities are aggressive or criminals.