Activist Hagit Ofran said she found messages on the stairwell of her Jerusalem apartment building on Monday reading "Hagit—you're dead."
Police spokesman Micky Rosenfeld says the suspect admitted to vandalizing the home, as well as the office of Ofran's employer, the Peace Now group.
Rosenfeld says he is also suspected in several other vandalism attacks. The man is to be formally charged in a Jerusalem court later on Tuesday.
Ofran monitors West Bank settlement construction for Peace Now. The group has frequently been a target of right-wing wrath in Israel, and Ofran says her home was targeted twice last November.