The IDF ordered four battalions to join existing military forces in the West Bank in the wake of a terror attack in which an Israeli couple was shot and killed. The decision was made following a security evaluation held by IDF General Staff on Thursday night.A Palestinian gunman shot dead two Israeli parents in a shooting attack on their vehicle in Samaria, between Elon Moreh and Itamar on Thursday night. The couple's four of their young children survived the attack without injury and were rescued by emergency responders from the bullet-ridden vehicle.The first of the extra units will begin arriving on Friday, to assist in searches for the terrorists and ensure IDF control of the area, and prevent a deterioration of the security situation.The main focus of this stage of the defense establishment's response will be on the intelligence front, a senior IDF said."There is certainly a change of atmosphere on the ground," the source said."The Shin Bet is carrying out a large range of activities, intelligence activities, to place our hands on the terrorists," the source added.Additionally, the IDF will surround a number of Palestinian villages in the vicinity of the attack to help the hunt for the terrorists.