Inspected this attic yesterday. Could figure what the stuff was. Wasn’t blood thankfully. My concern was it may be flammable - no odor at all. Possibly material used during a re-roof. Noted it as - (MR) There was a substance in the attic space that could not be identified. The dried dark liquid material was splattered against some of the wood trusses, insulation, and HVAC ductwork. Recommend monitoring this item for possible remedial action.