Two Calgary men have been charged with murdering a woman who was "targeted because of her history as a sex worker," police say.Investigators believe Chelsea Davidenas, 29, was killed hours after she was last seen on Feb. 17. Steven Aaron Zwick, 26, and Paul Joseph Rushton, 52, each face a charge of first-degree murder.The two men were described by police as "acquaintances." The case was initially investigated as a missing person file after the woman's family reported her disappearance to police.