Police said a mental competency evaluation will be given to Vayron Jonathan Nakada Ludena, 30-year-old Peruvian arrested last month for allegedly slaying a couple from Saitama Prefecture.

The evaluation will play a crucial role in the investigation into six murders he is suspected of committing.

Nakada was arrested Thursday in connection with murders that took place in three homes in September. He has been charged with fatally stabbing Minoru Tasaki, 55, and his wife Misae, 53, on Sept. 14 at their home in Kumagaya, Saitama Prefecture.