A man arrested in connection with the murder of a couple in a city north of Tokyo, where six people were found dead in the same neighborhood in September, will undergo surgery for a head injury, his lawyer said Thursday.

Defense counsel Ichiro Muraki was unable to meet Vayron Jonathan Nakada Ludena the same day because the 30-year-old Peruvian suspect was deemed as needing an emergency operation, the lawyer said in a news conference in Saitama.

Nakada was arrested Oct. 8 on suspicion of fatally stabbing Minoru Tasaki, 55, and his wife Misae, 53, on Sept. 14 at their home in Kumagaya, Saitama Prefecture.

Police are also investigating his possible involvement in the murders of four others — Miwako Kato, 41, and her two daughters, 7-year-old Haruka and 10-year-old Misaki, as well as 84-year-old Kazuyo Shiraishi — as footprints found at the three murder sites were similar to those of the suspect.

Investigators earlier said he has denied killing any of the six.

The police did not initially serve an arrest warrant as Nakada remained unconscious in hospital after plunging from a second-floor window at Kato's house on Sept. 16. He regained consciousness on Sept. 24.

He was discharged from hospital and was arrested on Oct. 8, but was hospitalized again on Oct. 15 based on a doctor's assessment.