The three-decade saga that led to the Crown Heights Tunnels: A group of anti-establishment yeshiva students from Israel took control of the Chabad-Lubavitch synagogue in Brooklyn and started digging.

Underground tunnels were discovered last week near the synagogue, and the rowdy yeshiva students rioted to block repairs.

The students, who come from the Israeli city Tzfat and are called Tzfatim, are “extreme Meshichists.”

Meshichists – or Messianists – are Chabad Hasidim who believe that their late leader, Rabbi Menachem Mendel Schneerson, is the Messiah, and despite his death in 1994, is still meant to reappear. Tzfatim are perceived to be, even by Meshichist standards, unusually fervent in their beliefs and have been involved in numerous incidents of violence and mayhem for nearly three decades.

When Rabbi Menachem Mendel Schneerson assumed the leadership of the Chabad-Lubavitch community in 1951, he delivered a seminal public address, which set the movement’s guiding principle for the next seven decades: “We are the last generation. It is our job to bring Moshiach” – the Hebrew term for the Messiah.

His followers heard something else too: their leader, in their view, was declaring himself the Messiah. What exactly he said and what he meant and how he meant it would be hotly debated over the years, but in a broad sense, Chabad Messianism became established Chabad doctrine.