“He was described as wearing a black T-shirt, olive trousers and had long hair in a pony tail.” “mid-twenties”
https://www.mirror.co.uk/news/us-news/breaking-capital-gazette-newspaper-shooting-12816369
(Sorry about the crap link - am searching for articles with this info from non-Euro outlets)
Meth user?
DailyMail always has a lot of pix and videos.
Very little about the shooter.