NICOSIA, Cyprus — The police in Cyprus were searching for more victims of what is believed to be a serial killer, in a case that has horrified the nation and led to accusations that the authorities have bungled the investigations and failed to adequately investigate when foreign workers were reported missing.

A 35-year-old National Guard captain who has confessed to killing seven women and girls and has been in custody for a week is facing multiple homicide charges. He was to appear in court on Saturday for a hearing, but has not been identified because he has not been charged.

The scale of the crime has shocked this country of just over a million people, where multiple killings are rare. The police chief, Zacharias Chrysostomou, told reporters last week, “This is a form of crime unprecedented for the norms of Cyprus.”

Hundreds of people held a vigil on Friday outside Cyprus’ presidential palace to mourn the dead. The organizer used a bullhorn to read out the victims’ names as well as those of other missing women, as others shouted, “Where are they?” Some participants held placards decrying “sexist, misogynist and racist” attitudes about women who work as housekeepers or in low-paying service jobs.

The discovery of a Filipino woman’s body in an abandoned mine shaft triggered the investigation that led to the captain’s arrest. The police identified her as Mary Rose Tiburcio, 38. Ms. Tiburcio and her 6-year-old daughter had been missing since May last year. Investigators say they believe that the missing 6-year-old was also killed.

Investigators zeroed in on the captain after scouring Ms. Tiburcio’s online messages. In court hearings, the police said he may have approached women on an online dating site.