An analysis by Shin Bet found the activists, angry about the demolition of their homes by authorities, have moved from spontaneous acts to organized planning, Haaretz reported Tuesday.
The planning includes the use of a database of potential targets, the Shin Bet analysis said.
Stopping the extremists presents a problem for authorities since their groups are difficult to infiltrate and carefully select escape routes before launching attacks.
The latest victim was a Peace Now leader who found graffiti threatening her life Monday on the front of her Jerusalem apartment and in a stairwell.
Police have not made any arrests in the case, Haaretz said.
The incident follows last week's vandalism at an Israeli army base in the West Bank, a response to the demolition of three homes at Migron Sept. 5.