Detectives have launched a murder investigation into the death of a man in his 40s who was found with blunt force trauma to the head on Monday morning inside a DUMBO apartment building that is comprised largely of supportive housing. Officers from the 84th Precinct responded at approximately 5:52 a.m. on Aug. 25 to a 911 call reporting an unconscious and unresponsive man inside an apartment at 90 Sands St., finding the victim with trauma to the head. Paramedics pronounced him dead at the scene.