Is this character responsible for some of the murders we see in Penny Dreadful?

In episodes 1 and 2 of the first season of Penny Dreadful, we see a mother and child murdered, and a gas lantern lighter and a prostitute.

In the first case, we later see Ethan Chandler among the onlookers at the scene, in the second case we see him having scratches on his hands later on.

In the final episode of the season, it is revealed that he is actually

As such, was he responsible for these murders?