Lawyer Jason Gratl filed the suit on behalf of the children of Dianne Rock, Sarah de Vries, Cynthia Feliks and Yvonne Boen against Pickton, his brother Dave, sister Lynda, the provincial government and the City of Vancouver
The suit claims police and the Crown failed to warn women in the Downtown Eastside that a serial killer may have been on the loose and raises concerns about the way police eventually told the missing women's families that their cases were linked to Pickton.
It also alleges the province and the city have ignored a recommendation of compensation made in a report by Missing Women Inquiry commissioner Wally Oppal.
None of the allegations contained in the suit have been tested in court.
Pickton was convicted of the second-degree murder of six women, but is a suspect in the deaths of at least 20 others, including the four named in the lawsuit.