A police official told The Associated Press that if the statements the suspect made while under questioning were true, he killed five women and two girls. All but one of the women was of Asian descent.
They include two Filipino women whose bodies were found in an abandoned mineshaft six days apart. Police previously said the suspect had admitted killing Marry Rose Tiburcio, 38, and the second woman, identified by Cypriot media as 28-year-old Arian Palanas Lozano.
Authorities searched the flooded mineshaft and a lake for signs of Tiburcio's missing 6-year-old daughter, Sierra. Investigators now think, based on the suspect's statements, that the girl was among his seven victims, the police official said.
A second police official confirmed the army officer claimed responsibility for seven killings. Both officials spoke on condition of anonymity because they were not allowed to publicly disclose details of an ongoing case.
The scope of the investigation expanded from a double-homicide to a triple earlier Thursday after authorities told a judge at a custody hearing the suspect had links to a third woman from the Philippines who vanished 16 months ago.
A witness told investigators the army captain had photos of 31-year-old Maricar Valtez Arquiola's temporary Cyprus residency permit that were taken the day she disappeared in December 2017. The suspect initially denied killing Arquiola but reversed himself after the court hearing and said he did, the police official said. The suspect can't be named publicly because he has not been charged with any crimes.
Under questioning Thursday, the captain also claimed three more victims, including a woman of Indian or Nepalese descent whose body he said he dumped last summer at a remote military gun range, the police official said.
Officers located a body at the range late Thursday after the suspect provided directions for where to look, the official said. The suspect also said he killed a woman of Romanian descent and her daughter.
Investigators plan to keep interrogating him to determine if he told the truth and for evidence he killed even more people. Authorities tracked down the officer last week by scouring Tiburcio's online activity.
Police said five British law enforcement officials, including a coroner, a clinical psychiatrist and investigators who specialize in cases involving multiple homicides, are coming to Cyprus to help with the investigation.
Activists who work to support immigrants to Cyprus have criticized the police force, alleging the department dragged its feet when the two women whose bodies were found in the mineshaft were reported missing nearly a year ago.
Police spokesman Andreas Angelides defended the force's actions. He told private TV station Sigma that Cypriot lawmakers turned down a police request last year for a law that would authorize law enforcement officers to access the personal data of missing persons.
Fire Service Chief Marcos Trangolas said divers finished exploring the mineshaft and plan to move the search for the missing girl Friday to a reservoir 8 kilometers (about 5 miles) away from the mineshaft.