Some new faces could be observed among the crowd of right-wing activists who on Sunday stormed the East Jerusalem house of the terrorist who killed eight yeshiva students earlier this month. The rioters did not all belong to the usual group of extremists who are all too familiar with the insides of interrogation rooms.

For instance, there was a group of minors from the big urban settlement of Efrat. One of the slain students' schoolmates was also present at the riot in the Arab neighborhood of Jabal Mukkaber. Two other rioters were a young man who works for the Ministry of the Interior and a new immigrant who came here just a few months ago.

But quite a few of the usual suspects were also there, especially those from the northern West Bank. The contingent from the settlements of Yitzhar and Ma'aleh Levona was especially noticeable, along with prominent extremists such as Baruch Marzel and Itamar Ben-Gvir.

All in all, police arrested 24 people - one of them carrying a knife. Thirteen of them were minors. Some, mostly the girls, refused to identify themselves to the police. Some of the parents were surprised to learn of the arrests. Others were anything but.

"It's not the first time that my son has participated in a demonstration like this one," one father told Haaretz. The father, who lives in Efrat, said that although he does not support his son's participation in such activities, the family nonetheless respects his actions. "I find it hard to believe that he participated in throwing stones. That is not our way," he added.

Another father said his son was devastated after the killing of eight students at Mercaz Harav Yeshiva. "I guess he felt that calling for the destruction of the terrorist's home was the least he could do," the father explained.

This is the brew that produced the riot - which was premeditated. Police, seeking to allow the right wing to "blow off some steam," failed to anticipate where things would lead.

But it is hard to see how policemen could have prevented the riot even if they had anticipated it. Jabal Mukkaber is a large village. Just the area around the Tayelet (Haas Promenade), where the official demonstration took place, contains dozens of potential entry points into the neighborhood.

Jerusalem has seen other riots by right-wing extremists in response to terror attacks. During the second intifada, residents of Beit Safafa - a minority of whom were in the habit of hurling stones at Jewish vehicles - had to endure violence from right-wing protesters. The killing of two Jewish boys, Lior Tubul and Ronen Karmani, in August 1990 also produced a Jewish mini-intifada that culminated in the killing of an Arab civilian.

But the security services mostly fear a reprise of the Jewish Underground of the 1980s, which could result in multiple shooting attacks against Arabs. The Shin Bet security service's Jewish Division knows well that the rioters are not those who would squeeze the trigger. In the past, at least, Jewish terrorists opted to refrain from participating in loud political protests.

Talk of the need for revenge, albeit state-sponsored, is deeply disconcerting to the Jewish Division. The "New Sanhedrin," a group of rightist rabbis, recently issued a ruling defining revenge as "one of the foundations of justice." The organization's "permanent tribunal" ruled last week that "the security forces' failure to mete out justice to our enemies puts the burden of revenge on others." This is seen as an implicit call for individuals to take the law into their own hands.