After failing to catch the Blind Tarot Killer, Mattheus could only head back to the Crown townhome after checking on Artemius Holmes.
Because, while they failed to catch the killer, Holmes had managed to close the distance.
Unfortunately, the detective hadn't got a good look at the killer himself, somehow being sneaked up behind and hit with a face full of hallucinogenic powder. Considering how juiced up the substance was, clearly a product of alchemy, the sergeant's account on the Blind Tarot Killer's appearance wouldn't have been reliable anyway.
Mattheus was not sure how they could keep the serial killings under wraps anymore, when the use of occult energy was present, but he would leave that to Artemius Holmes to deal with. One didn't have to be an occultist to use that kind of substance, after all, so maybe the detective could swing the argument that way.
Getting the military more involved would just be troublesome in the long run.