Parenting, or lack of it can certainly contribute. Some are just bad though.
This family produced one of these murderers and a police detective and two state troopers.
"Combs was 17 when he and Danny Lee Hill, who was 18 at the time, stopped Fife on Sept. 10, 1985, in a wooded area near Palmyra Road SW, as the boy rode his bike to a Boy Scout meeting. Fife died two days later after he was beaten, sexually tortured, strangled with his underwear, set afire and left for dead. He was barely alive when he was found several hours later by his father and brother-in-law."
Family can certainly contribute. But not always the case.
-Jake