Monday's announcement that indictments were filed against residents of the Beduin village of Houra in the Negev on suspicion of membership in, and support for, the Islamic State terrorist organization should be cause for concern.The development should concern not only the Shin Bet (Israel Security Agency), Israel Police and the other law enforcement authorities. To an even greater degree, it should set off warning lights for the Israeli Arab leadership: MKs, mayors, local councils, journalists and the intellectual community.Among those indicted were teachers who worked in schools in Houra and Rahat and spread the doctrine of Islamic State and its leader, Abu Bakr al-Baghdadi, to their students. Muslim youths, often elementary school aged children, are a central target of the sophisticated digital propaganda from the murderous Islamic State group that controls parts of Syria and Iraq. Everyday, Islamic State posts pictures on the Internet of children carrying weapons that have been subject to brain-washing indoctrination. They have also posted gruesome videos of children cutting off the heads of captives who have fallen into the hands of Islamic State.This is not the first time that indictments have been filed against Israeli Arabs that have formed Islamic State cells in which they learned and spread the doctrine of the group and planned to join the ranks of the organization for its wars. Three members of the new cell planned to set out on a religious pilgrimage to Mecca in Saudi Arabia and using this as cover, to make contact with Islamic State operatives. Among those in the networks which have been uncovered, there were not only frustrated and unemployed youths, there were also teachers, a doctor and a lawyer.According to security sources, 47 Israeli Arabs have left Israel and joined the ranks of Islamic State or al-Qaida in Syria. The number has likely grown. A small number of them who returned were tried and sentenced to prison time.At this point it is still a small number, perhaps 100, of Israeli Arabs who fallen captive to Islamic State's ideology and cult of death. This is negligible in an Israeli Arab population that numbers some 1.5 million people. In order to prevent these isolated cases of bad apples from turning into a growing phenomenon, responsibility and a quick denunciation without stuttering or excuses is required from the pillars of the Israeli Arab community, as well as a serious public diplomacy and education effort.The effectiveness of the Shin Bet, which is following Islamic State activity on social networks and deals mainly in foiling threats, will not suffice to prevent the slide down the slippery slope.