During a press conference Monday morning, District Attorney Risa Ferman described the horrifying, bloody scene inside the McAndrew's Upper Merion home. She said, we know what happened, but we may never know why.
Ferman told reporters, "There is really nothing at this point that can tell us why these events transpired, what happened to provoke them, and really what went on inside of his head at the time."
23-year-old Joseph McAndrew Jr. is charged with three counts of 1st and 3rd degree murder.
Police were called Saturday night to 203 Holstein Road in Gulph Mills for the report of a domestic dispute. A tenant who lives in a garage apartment in the house was the one who called authorities. He said he heard Susan McAndrew yelling for him to call 9-1-1, followed by an eerie silence.
When they arrived, police found Joseph McAndrew in the driveway with blood soaked pants and shoes.
When he was asked what had happened, police say he answered, "Extermination."
When he was asked who did it, he responded, "Attacker."
Who were the victims? He responded, "Person named brother, person named mother, person named father."
The DA says McAndrew had a history of mental health issues. But investigators don't know what kind of treatment, if any, he may have gotten over the years. Sources say Joseph stayed at home, living on a mental health disability check.
His twin brother James recently graduated from Penn State University.
Both boys were described as brilliant, but followed two very different paths in life.
"We know [James'] twin brother - the man who took his life - was someone who had struggled over the years after high school. [He] did not go to college - he was very much a loner and an introvert," explained Ferman. She continued by saying, "We know that his twin brother was someone who was a great supporter of his through his life."
Investigators say McAndrew, essentially, butchered his family using an 18-inch long dagger-like sword.
He apparently caught his father by surprise, the only victim with no sign of defensive wounds.
It also appears that James suffered numerous defensive wounds, apparently trying to save his parents.
Joseph McAndrew Jr. is being held without bail right now. He faces his first preliminary appearance in court next Tuesday.