One example of Hamas practices that are modeled after the Israeli army is the "wanted list." According to Haaretz,
"Hamas was not using a random hit list. Every Hamas patrol carried with it a laptop containing a list of Fatah operatives in Gaza, and an identity number and a star appeared next to each name. A red star meant the operative was to be executed and a blue one meant he was to be shot in the legs - a special, cruel tactic developed by Hamas, in which the shot is fired from the back of the knee so that the kneecap is shattered when the bullet exits the other side. A black star signaled arrest, and no star meant that the Fatah member was to be beaten and released. Hamas patrols took the list with them to hospitals, where they searched for wounded Fatah officials, some of whom they beat up and some of whom they abducted."
The Haaretz article concludes with this passage about Hamas's execution of civilians from the Bakr family. For the record, I haven't read about this anywhere else:
"Aside from assassinating Fatah officials, Hamas also killed innocent Palestinians, with the intention of deterring the large clans from confronting the organization. Thus it was that 10 days ago, after an hours-long gun battle that ended with Hamas overpowering the Bakr clan from the Shati refugee camp - known as a large, well-armed and dangerous family that supports Fatah - the Hamas military wing removed all the family members from their compound and lined them up against a wall. Militants selected a 14-year-old girl, two women aged 19 and 75, and two elderly men, and shot them to death in cold blood to send a message to all the armed clans of Gaza."