That Cold Day in the Park is a 1969 suspense film directed by Robert Altman and starring Sandy Dennis, based on the novel of the same name by Peter Miles and adapted for the screen by Gillian Freeman. The movie was filmed on location in Vancouver, British Columbia, where the events occur. The supporting cast features Michael Burns, Luana Anders, John Garfield, Jr., and Michael Murphy. The picture was screened at the 1969 Cannes Film Festival outside of the main competition.
Source: Wikipedia