What... isn't it normal to assume that the one that invited everyone for a drink is the one who is known as a drunkard?
Also the author suspiciously omits the fact that the lawyer is actually a possible suspect because he also did not have an alibi. He just wasn't shown to have any motive, which makes him more suspicious because the real motive usually appears last.
This was a subpar chapter, but anyway, thanks for the scanlation!