Rafael Popeye Santiago, 41, was found dead in a second-floor bedroom of his home on Holly Road in Northeast Philadelphia on October 5, 2014. He was discovered in a pool of blood and the medical examiner determined he sustained two gunshot wounds to the face; the death was ruled a homicide.

Police arrested and charged a 23-year-old man named James Kelly, identified as Santiago’s stepson, with murder and other offenses. Authorities say Kelly allegedly shot Santiago during an argument; Kelly was denied bail and held at the Curran-Fromhold Correctional Facility following his arrest. Reports state two gunshots were used in the killing and the shooting arose from an escalating argument between the two.

What details about the night of October 5, 2014, or the household dynamics are still missing that could help explain how the argument turned deadly?