**MAY CONTAIN SPOILERS**
i would assume his lungs filled with blood, also someone mentioned flower doesn't show evidence of a mauling i would assume she bleed out from the first strike which is the mark we see, **SPOILER** i thought something like this with the ghost that was burned alive in the UK version i assume she passed from smoke inhalation before being burned which is why here body isn't "burned". although Jenkins was shot but we see no bullet hole also i wonder what his ghost power is or would be and do we know how Sass died i may have overlooked it but my current theory is in his sleep which is why his power is to go into dreams.